To Spray or not to Spray(foam)

JohnnieMo · Dec 27, 2014

I'm designing a 37x26 with 10' walls. I'm tight on funds but also tight on time. I'm looking to do this build next summer. Given that I don't have a lot of time I see close cell spray foam making a lot of sense. That way I could build it, spray it, then have all winter to run electrical, water, air etc before installing drywall.

Another factor is the ceiling. One half is scissor (for the lift) and the other is a loft that needs to be warmish (I.e. Inside the warm zone). It seems so much easier to spray the back of the roof sheathing rather than having to create air space, stuff batting, then struggle to to install vapour barrier between all those joists.

Cost of foam in town is $2.40 sqft installed for 2" closed cell.

My thought is to do 2x6 walls with 2" foam, and 3.5" of batt. Same for the ceiling. However is it overkill to spray and batt a building where the doors let cold air rush in every couple hours???? That would get me R28 or there abouts.

Couple questions:

1) Can you spray directly to the back of roof sheathing?
2) is it worth doing both spray and batt?
3) Do the garage doors remove any heat savings I may gain?

Looking at radiant heat mounted near the ceiling.

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DEnd · Dec 28, 2014

1) What's your snow load? The snow load will determine if you need to vent the roof or not, and thus if you can spray foam directly to the roof sheathing or not. If you have a high snow load (50+ psf) then you really need a vented roof to keep from having ice dams, below that and an unvented roof with insulation to the sheathing and a good air seal works well.

2) The reason to do spray foam is to create a good air and moisture barrier as well as for insulation. Therefore Flash and bat can work well. There are other ways of doing the same thing without foam. Poorly installed foam can be just as bad as other forms of insulation poorly installed, but it is harder to see where the foam installation has problems. You may want to consider the REMOTE wall system (http://www.cchrc.org/remote-walls) or the PERSIST (http://www.energyauditingblog.com/were-getting-esoteric-here-persist-wall-systems/) system.

3) While the garage doors opening does cause an influx of cold air, they really aren't opened enough that they eliminate the need for insulation and air sealing. That is unless you are leaving them open, then you are just wasting energy trying to heat the space. You may want to consider a radiant Infrared heating system, since it will heat the objects and thus also the people directly which allows for a lower air temp to be comfortable.

If this is going to be a hobby garage then you should plan to also install some form of ventilation. For most garage type hobbies (wood working, auto repair, etc...) I'm comfortable recommending a ventilation rate of 0.75 air changes per hour (ach). That is about 2.25 the amount of ach than is recommended for houses, the reason for this is garage type hobbies produce more pollution than is typically found inside houses. While this absolutely raises the cost to heat the space it only needs to work while the space is occupied. I think a large bath fan would likely get the CFM needed to provide that level of ventilation (150 cfm), but that depends on the cubic feet in your building. In searching for ventilation equipment you may run across an ERV (energy or enthalpy recovery ventilator), these work by allowing the water to be brought back inside the building envelope, or to be pulled out of incoming air. I would not use one of these in a garage, they do provide great energy savings for ventilation, but they may also allow pollutants (particularly gaseous pollutants) back into the building, as some of those may likely follow the water.

JohnnieMo · Dec 29, 2014

Thanks for the reply DEnd. It took me a while to review your info and find out some of the answers.

As for snow load, I'm not very clear on how to figure this out. The best I can find is this document (http://www.leductruss.com/Premier_Truss_Manufacturer/Leduc_Truss_-_Dealer_Page_files/GSL Chart.pdf) which cites the Ground Snow Load for the City of Calgary at 22.97. When comparing to other parts of the province, I'd say this is accurate. We get a fair amount of snow here, but it melts frequently. A place like Banff, however, is only an hour from here, but has a load of 75.

I don't quite understand how snow load would impact my choice of insulation. Can you expand upon that? Of note, 24" OC is a pretty standard roofing practice in the city. My slope will be quite a bit higher than the minimum.

I reviewed the data you provided on REMOTE and PERSIST. Very interesting options. I'm not entirely sure they are appropriate for me however. I love the idea of free and open wall cavities, but I think I could get the same by going with a 2x6 wall, half full of foam, at a cheaper price. If I was building a house, this would be in the running however.

This will be a parking garage first, and a hobby garage second. I will consider adding some form of ventilation - good idea. It's not a big expense to add an exhaust fan.

Regarding installation of spray foam, is this something a guy can do himself? My family (who are all tradespeople) suggest we do it ourselves. However I work at a software company, so its not exactly up my alley. They say you can buy the tanks of it and spray with an air compressor. Is this feasible? Cost effective?

Randy in Maine · Dec 29, 2014

Price it out using SIPS before you commit.

JohnnieMo · Dec 29, 2014

SIPS looks fascinating. Their website is a bit odd however it looks like they are Canadian. Could be beneficial for me. I will contact them and see what they say.

I wonder how you cut in windows and doors.... or nail into the wall the hang things. And how about running electrical? I'll do some research. Are there any builds on GJ where guys have used it?

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theoldwizard1 · Dec 29, 2014

"Flash and batt" is the best bang for your buck when it comes to insulating "stick built" structures.

I strongly recommend that you get a quote on Structured Insulated Panel (SIP) construction. 6" wall, 12" ceiling. The insulation is built into the panels so that once it is up, it is insulated. Plus construction is fast. Many SIP suppliers will provide construction plans for free or very low cost.

Another benefit of SIP construction is you have no trusses or rafters. It does require a structural ridge beam, typically a glu-lam, and supporting posts built into each gable end.

theoldwizard1 · Dec 29, 2014

JohnnieMo said:
I wonder how you cut in windows and doors.... or nail into the wall the hang things. And how about running electrical? I'll do some research.

I general, all opening are pre-planned and the panels are built to accommodate all openings. The interior and exterior are OSB, so for light weight thing you can use hollow wall anchors and possibly even toggle bolts. Typically 2 vertical panels use a 2by at the seam so it is effectively a stud, just spaced 4' apart.

There is a chase (hollow tube) "cast" into each wall for electrical. Plumbing should be run up from the floor.

There are a lot of manufactures, but their products and construction techniques are similar. There are a couple of good downloads at INSULSPAN TECHNICAL INFORMATION

There are also a lot of videos of YouTube.

theoldwizard1 · Dec 29, 2014

Regarding snow load - It looks like you a spec'ing a 10:12 pitch. I would not worry too much about it, but I am certain that the design will accommodate your load.

What are your plans for heat, if any ?

larry4406 · Dec 29, 2014

I have to say SIP's are mighty impressive.

Used SIPs panels on the roofs. These were screwed into Douglas fir rafters. The walls were "flash and batt".

Structures were so tight the toilet bowl levels fluctuated as the exterior doors opened and closed.

http://aiadc.com/sites/default/files/Wash35.JNNMVFWKTFD.pdf

dfiler2 · Dec 29, 2014

Spraying the back side of the roof sheeting is a great way to go, you don't need to worry about condensation and it will greatly strengthen the roof. I am just building a shop, I put up 2x6 walls then sprayed them with 1.5 inches of foam then put in 3.5 inch batts, I love it.
That being said, using SIPs would be a really good way to go.

3pedal · Dec 29, 2014

I bought a place with a pole barn already here. I am getting 3 inches of foam sprayed as soon as the weather allows. I might put in batts later as I finishes the inside later.

I would recommend at least putting in the exterior electrical before you spray in the foam.

JohnnieMo · Dec 29, 2014

I like the SIPS concept because it reminds me of building subwoofer boxes. I've built a lot of those.... I'll definitely look around for a local supplier.

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DEnd · Dec 29, 2014

JohnnieMo said:
I don't quite understand how snow load would impact my choice of insulation. Can you expand upon that? Of note, 24" OC is a pretty standard roofing practice in the city. My slope will be quite a bit higher than the minimum.

Regarding installation of spray foam, is this something a guy can do himself? My family (who are all tradespeople) suggest we do it ourselves. However I work at a software company, so its not exactly up my alley. They say you can buy the tanks of it and spray with an air compressor. Is this feasible? Cost effective?

Snow load has zero bearing on your insulation choice, only on if you want to ventilate your roof or not. This is because snow is a form of insulation (approx. R-2 per inch depending on the type of snow), around 50 psf the R-value of the snow is enough to trap the heat escaping from the roof (of a non vented roof assembly) causing the bottom level of snow on the roof to melt. The roof slope then drains the water down towards the overhangs where roof surface temps are lower causing it to refreeze creating ice dams.

While you certainly can spray the foam yourself, I do not recommend it. It is very easy to make mistakes, and fairly difficult to tell if you have done so. When you are interviewing contractors find out how they insure that there are no unseen gaps or holes in the insulation, and how they insure that the correct levels of spray foam have been applied.

Don't discount REMOTE or PERSIST quite yet, you can even use some of the basic Ideas without going whole hog. For example the exterior rigid foam. If you use enough for your climate then condensation on the sheathing and studs is eliminated which helps keep moisture content of the walls low, increasing building durability. There are used sources of rigid foam available and they are perfectly fine to use for the most part. You can still insulate the stud bays with batt insulation, to inexpensively increase energy efficiency.

Another Idea in those systems that is worth pursuing is the exterior air barrier, with spray foam this is not necessary, but it is a good idea for other types of insulation.

Regardless of the insulation technique you use I suggest you use the rain screen detail. This detail increases the time required between repainting, and helps the structure dry.

SIPs are not a bad option, however they are more expensive than stick building. Their advantage is that they go up much faster, this results in savings compared to stick built if you are paying for labor, and have a construction loan.

dfiler2 · Dec 29, 2014

There are two things you are addressing here that are not really related. It is important to ventilate an attic because warm air and moisture will escape the building and in an unvented attic the moisture will condense on the under side of the cold roof,usually in the form of frost, when it warms up it will melt and can cause damage to the building. Keeping the attic ventilated will ensure that condensation will not build up in the attic. By spraying foam on the underside of the roof you eliminate the condensation issue, no moisture will reach the underside of the roof. you would still need to control the moisture, however this is rarely an issue in a shop.The other issue of an ice dam is caused by heat escaping the building and melting snow just as you say. This is a problem in buildings with an overhang, as the snow is melted it runs down the roof until it reaches the overhang which has no heat loss. The water can freeze and cause an ice dam. The only way to keep that from happening is to clear the snow from your roof or use or use a heat cable to melt the ice when it builds up.

JohnnieMo · Dec 30, 2014

theoldwizard1 said:
Regarding snow load - It looks like you a spec'ing a 10:12 pitch. I would not worry too much about it, but I am certain that the design will accommodate your load.

What are your plans for heat, if any ?

My plan keeps changing. I was originally planning for an overhead radiant heater however now that I am pouring a 100% new floor, I'm considering in-slab radiant.

Lots to ponder here. I am leaning towards 2x6 stick construction with flash and batt. I looked at doing the spraying on my own but the price points are actually more expensive than the hired contractor.

The SIPs is also an option but I'll need to find a good supplier here in Calgary'. I like the overall premise of it but I have no working knowledge on install. Conversely I've got a buddy who frames for a living and a brother in law who does roofing. (and a cousin who does concrete). They are all raring to go so I don't want to throw a curveball that negates their skill set.

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JohnnieMo · Dec 30, 2014

DEnd said:
Snow load has zero bearing on your insulation choice, only on if you want to ventilate your roof or not. This is because snow is a form of insulation (approx. R-2 per inch depending on the type of snow), around 50 psf the R-value of the snow is enough to trap the heat escaping from the roof (of a non vented roof assembly) causing the bottom level of snow on the roof to melt. The roof slope then drains the water down towards the overhangs where roof surface temps are lower causing it to refreeze creating ice dams.

While you certainly can spray the foam yourself, I do not recommend it. It is very easy to make mistakes, and fairly difficult to tell if you have done so. When you are interviewing contractors find out how they insure that there are no unseen gaps or holes in the insulation, and how they insure that the correct levels of spray foam have been applied.

Don't discount REMOTE or PERSIST quite yet, you can even use some of the basic Ideas without going whole hog. For example the exterior rigid foam. If you use enough for your climate then condensation on the sheathing and studs is eliminated which helps keep moisture content of the walls low, increasing building durability. There are used sources of rigid foam available and they are perfectly fine to use for the most part. You can still insulate the stud bays with batt insulation, to inexpensively increase energy efficiency.

Another Idea in those systems that is worth pursuing is the exterior air barrier, with spray foam this is not necessary, but it is a good idea for other types of insulation.

Regardless of the insulation technique you use I suggest you use the rain screen detail. This detail increases the time required between repainting, and helps the structure dry.

SIPs are not a bad option, however they are more expensive than stick building. Their advantage is that they go up much faster, this results in savings compared to stick built if you are paying for labor, and have a construction loan.

Thanks for the explanation. I completely get it now.

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rancherbill · Dec 30, 2014

It looks like a neat project.

I think you have been looking at too many American sites. Spray foam is rarely used in the Calgary area. The reason is that it is very expensive to get the RSI (R-value) that is necessary here.

I build a house and triple garage. I went to many sites and looked how the big builders were doing it. There is a HUGE difference in construction methods in Canada.

If you are insulating it implies you are heating and if you are heating you should be building at residential standards.

I think if you talk to a truss guy they can buld your trusses so you can get lots of batt or fiberglass installed at a substantially better price than spray foam.

Go to Rona and talk to the people at the truss plant in Calgary. Show your basic plan and they will be able to offer suggestion and design great trusses that do exactly what you want.

jvitez · Dec 30, 2014

JohnnieMo said:
My plan keeps changing. I was originally planning for an overhead radiant heater however now that I am pouring a 100% new floor, I'm considering in-slab radiant.

I am leaning towards 2x6 stick construction with flash and batt. .

I've got a buddy who frames for a living and a brother in law who does roofing. (and a cousin who does concrete). They are all raring to go.....

With the above information, your choices are obvious, to me..... :lol:

1. Stick built 2x6.
2. In floor radiant heat, no question.
3. Roof built like a Canadian house, with vapour barrier on the ceiling, a ventilated attic space, and R50 cellulose for your climate.
4. Either borrow the money to do high density "2 lb" closed cell polyurethane spray foam for all the walls completely, no flash and batt, or install 1.5" of Durofoam EPS rigid insulation on the exterior sheathing, and insulate the stud bays with Roxul.

Use the resources (friends) you have at your disposal. No point in getting to ahead of the curve with SIPS for a pretty simple build, unless you can find an experienced contractor able, willing, and has the time to do the work.

The benefit to closed cell foam in the walls is R7 per inch (about R36-37 taking into account conductive heat loss through the studs), complete air and vapour sealing, a stronger wall, it's waterproof, and no need for Tyvek/Typar. Hire it out so it'd done for you. The negative is cost, plus you still have conductive heat loss through each stud.

The benefit to Durofoam exterior sheathing and Roxul: you eliminate conductive heat loss through each stud, both products are made in Canada (Plasti-fab products in your province), Roxul is waterproof, costs less than spray foam, and you can install both rigid board and Roxul yourself saving labour costs. The negative is you need Tyvek/Typar/etc on top of the Durofoam, a sealed vapour barrier on the inside of the stud walls, and you have to do it yourself. It makes an effective R20.5 wall.

Blown-in loose fill insulation is the cheapest way to insulate and attic, it's standard and it works in our climate. You could DIY, but many people have said hiring it out costs the same or even cheaper, so why not let someone else do it?

Do in-floor radiant heat. Do it! You'll never regret i

theoldwizard1 · Dec 30, 2014

larry4406 said:
Structures were so tight the toilet bowl levels fluctuated as the exterior doors opened and closed.

An interesting way to describe the "tightness" of a structure !

theoldwizard1 · Dec 30, 2014

jvitez said:
Use the resources (friends) you have at your disposal. No point in getting to ahead of the curve with SIPS for a pretty simple build, unless you can find an experienced contractor able, willing, and has the time to do the work.

I disagree ! SIP construction is fast and does not require a big crew. I does require a crane of some sort, so hire that out.

The OP's 37x26 could be completed in 2 days (minus shingles), with a crew of 3-4. Erecting the walls can be done with an all terrain forklift or even a tractor with a bucket although a crane is much faster.

Check YouTube. They show building an entire house (minus shingles, door and windows) in one day.

I want to see someone build a stick frame or pole building and have it completely insulated in that kind of time.

Do in-floor radiant heat. Do it! You'll never regret it !

I agree 110%

jvitez · Dec 30, 2014

theoldwizard1: I get what you're saying exactly. I think stick built will and probably should go the way of the buggy whip. ICF construction and SIPS are far better building methods. But.....

The construction industry is really conservative. SIPS need a professional crew, so the OP can't add his own labour to reduce costs nor call in favours from his friends. Yes, SIPS are really fast and much better in energy efficiency. But with the parameters the OP gave us, including trying to keep costs down as much as possible and being able to do some of the work himself, tried and true stick built makes the most sense, for him, not for everyone.

When we built our house I really wanted the whole thing done as ICF construction. The small custom homebuilder we picked wasn't interested, so I wasn't going to push him to go in a direction he didn't want to go, as that's how you get an inferior product. But now 8 years later ICF is much more common. It's still more expensive than stick built, so more commonly used for basements only. They use stick built for the upper floors. A buddy built his house 2 years ago in exactly this way. But haven't seen any SIPS yet, at least in residential construction.

The OP is in Calgary which is an oil-boom-fueled expensive, busy, labour-shortaged city. Canada didn't rise as high as the US pre-2008, but we didn't fall very far afterwards either.

My point isn't that SIPS construction is bad, it's actually a great way to build, just not for the OP and his specific circumstances.

Randy in Maine · Dec 30, 2014

I put up my own SIPs along with 2 of my buddies. Took about 3 days to have all 4 walls up. Cold roof with trusses. Very tight.

I was amazed at how little waste the project generated (which costs me about $100 a ton to get rid of).

Nor'Easter · Dec 30, 2014

Randy in Maine said:
I put up my own SIPs along with 2 of my buddies. Took about 3 days to have all 4 walls up. Cold roof with trusses. Very tight.

I was amazed at how little waste the project generated (which costs me about $100 a ton to get rid of).

This.

I install SIPs professionally along with timber frames. They are pretty basic and a small building is cake, especially if you don't have dormers, hips, or valleys to work with.

theoldwizard1 · Dec 30, 2014

DEnd said:
SIPs are not a bad option, however they are more expensive than stick building. Their advantage is that they go up much faster, this results in savings compared to stick built ...

Yes, SIPs cost more than stick built, but do they cost more than fully insulated stick built ! I have never seen a documented cost analysis either way.

OP did state that time was somewhat of an issue.

theoldwizard1 · Dec 30, 2014

jvitez said:
The construction industry is really conservative. SIPS need a professional crew, so the OP can't add his own labour to reduce costs nor call in favours from his friends.

Actually there is a video on YouTube of a guy building a SIP wall by himself. I think he is nuts !

My point isn't that SIPS construction is bad, it's actually a great way to build, just not for the OP and his specific circumstances.

Randy in Maine said:
I put up my own SIPs along with 2 of my buddies. Took about 3 days to have all 4 walls up. Cold roof with trusses. Very tight.

I was amazed at how little waste the project generated (which costs me about $100 a ton to get rid of).

Nor'Easter said:
I install SIPs professionally along with timber frames. They are pretty basic and a small building is cake, especially if you don't have dormers, hips, or valleys to work with.

Randy and Nor'easter have "real world" experience.

The key to DIY SIP is lots of research and planning. Plenty of the proper size screws and several impact drivers with spare batteries. Probably a battery operated caulking gun for those couple of hundred tubes of adhesive also !

And a good crane operator who knows how to rig and lift SIPs.

theoldwizard1 · Dec 30, 2014

Randy in Maine said:
I put up my own SIPs along with 2 of my buddies. Took about 3 days to have all 4 walls up. Cold roof with trusses. Very tight.

What do you mean by "cold roof" ?

Randy in Maine · Dec 30, 2014

Here is where I got my SIPS from ....

http://www.murus.com/

They will send you an assembly manual if you ask. My "kit" for my 28x40x12 garage came with spray foam (for between the panels), construction adhesive and a bunch of 8' long "headlock" screws (for the corners). The panels were only about 3.5 pounds per square foot and mine were at most 4' wide and 12' tall. Cutouts are there for windows, man doors, and garage doors. Mine SIPS are 6 5/8" thick with 5 5/8" closed cell foam between the 1/2" OSB sheets. Me (Mr. Bad Back), my carpenter buddy, and a 19 year old helper "walked" them up. We didn't really know what we were doing and got the 4 walls up in about 3 or 4 days in the winter. The ones I used "lock in" with a 2x6 on the top and the bottom of the panels with adhesive adn lots of nails. The bottom 2x6 is glued and screwed to a PT 2x8 screwed to the foundation wall.

The ceiling panels in my garage are the "roof insulation" or ceiling panel SIPs" (about R-38 or so). On top of that are the trusses and then the roof. I have soffit and a ridge vents so the bottom of the roof is the same temp as the top of the roof. No ice dams for me. My local lumber comapany made the trusses and I made them stronger than they had to be (2x6s 16" OC vs 2x4 24" OC).

I am not saying that they are the best set up for anything but worked really well in my case. You can propbably do it cheaper (although not as tight) with stick built 2x6s and spray foam, but not if you include labor and waste if you have to pay for that.

My wife's next husband is going to love it.

jvitez · Dec 31, 2014

Randy in Maine said:
My wife's next husband is going to love it.

I have lots of life insurance, but my wife says I'm still worth more alive. But if I kill myself working so much at least I'll leave a rich widow. Never thought how her next husband will like the garage.

theoldwizard1 · Dec 31, 2014

Randy in Maine said:
My SIPS are 6 5/8" thick with 5 5/8" closed cell foam between the 1/2" OSB sheets. Me (Mr. Bad Back), my carpenter buddy, and a 19 year old helper "walked" them up. We didn't really know what we were doing and got the 4 walls up in about 3 or 4 days in the winter. The ones I used "lock in" with a 2x6 on the top and the bottom of the panels with adhesive and lots of nails. The bottom 2x6 is glued and screwed to a PT 2x8 screwed to the foundation wall.

That is pretty typical wall construction, using a single top plate and a double bottom plate. Interesting that 2-3 guys goes could "walk" up a 12' tall wall section !

What did you use for splines ? Some manufacturers spec "2by", some just use strips of 1/2" OSB.

The ceiling panels in my garage are the "roof insulation" or ceiling panel SIPs" (about R-38 or so). On top of that are the trusses and then the roof.

Now I understand "cold roof" ! This is a bit more expensive than just SIPs resting on a structural ridge beam, but you don't need a crane to install the structural ridge beam and the roof panels.

I am assuming the ceiling panel went up before the trusses ? If yes, did the have I-joist built into the sides for support ?

I have soffit and a ridge vents so the bottom of the roof is the same temp as the top of the roof. No ice dams for me. My local lumber comapany made the trusses and I made them stronger than they had to be (2x6s 16" OC vs 2x4 24" OC).

I guess, in theory, you could hang the ceiling panels from the trusses (assuming their load was included in the truss load calculation)

You can propbably do it cheaper (although not as tight) with stick built 2x6s and spray foam, ...

I really don't think the costs would be that much different, unless you are saying your labor is free !

theoldwizard1 · Dec 31, 2014

jvitez said:
I have lots of life insurance, but my wife says I'm still worth more alive. But if I kill myself working so much at least I'll leave a rich widow. Never thought how her next husband will like the garage.

I have no life insurance. Not sure why the wife keeps me ! :bounce:

Randy in Maine · Dec 31, 2014

I could have bought cheaper SIPs but I wanted the good ones for the some extra money. I was focusing in on the long term cost to keep it heated and opted for the thicker ones that most people use in a house. I was sanding my 1x8 shiplap pine for the interior walls during Superstorm Sandy and the sawdust just sort of "hung" in the air even though it was wicked windy. Little infiltration anywhere.

My heaviest wall panels were about 3.5 pounds per square foot x 12' tall x 4' wide or about 170 pounds max. Once we had three of them put up we pretty much had the procedure it down and it went pretty fast.

The wall panels either locked together with "cams" or 2x6s in the corners and at windows/doors. Just my ceiling panels used splines and they were supplied. Spray foam on all those "foam/foam" joints. Construction adhesive on the wood/wood joints. Lots of nails and headlocks.

After the walls went up we locked them in the top using the 2x6s and the trusses mounted on top of those with brackets and nails. They call them "hurricane collars" here. A air power "palm nailer" made that go fast.

I used a drywall lift to raise the 100 pound 4'x8' ceiling panels the 12' up to the trusses (that were designed for the weight) and secured to the trusses with the 8" headlocks. that tightened up everything. I then sheetrocked the bottom side of the ceiling and painted it white. T5 lights, ceiling fans, and the hardware to run the garage doors is about all that is up there attached to the ceiling panels. I opted for no storage above the ceiling and instead store everything on the walls. It works pretty good for what I do.

theoldwizard1 · Dec 31, 2014

Randy in Maine said:
I then sheetrocked the bottom side of the ceiling and painted it white.

Good idea ! Not only does it look nicer, but even 1/2" sheetrock gives you some fire rating !

Did you and the others just "man handle" the trusses or did you pay someone to stack them on top of the walls for latter positioning ?

Randy in Maine · Dec 31, 2014

We got the trusses up there with 4 of us. The lumber company I got them from told us they would have just "delivered them up there" if we had asked.

JohnnieMo · Dec 31, 2014

Thank you all for the feedback. Its been a busy time of year so I haven't been able to put a lot of time into research. So bear with me as I get through all the good suggestions.

rancherbill said:
It looks like a neat project.

I think you have been looking at too many American sites. Spray foam is rarely used in the Calgary area. The reason is that it is very expensive to get the RSI (R-value) that is necessary here.

Thanks Bill. However I completely disagree with your point about spray foam in Canada. Mike Holmes does almost 100% of his shows in Canada and spray foam is the only thing he uses. You can get a far higher R rating with foam than with batt. I also have friends who just finished new builds with spray foam. I would agree that its not the norm yet, but its not unusual.

My house was built in 1974 and has an R rating of something like R8. My existing garage is probably about R10 and I can't even find vapour barrier! I think no matter what I do, it will be better than what is there now. Even 2" of spray foam to get me a vapour barrier and R14 would be the best thing I've got on my property!

theoldwizard1 said:
I disagree ! SIP construction is fast and does not require a big crew. I does require a crane of some sort, so hire that out.

I do have access to a crane. I've sent a query to my buddy who runs his own construction company (does framing) to see if he has ever done SIPs. I'm starting to really like this idea, although I need to understand more about how you construct the roof (not the ceiling!). I need to get my vaulted ceiling above the lift and the loft on the other side. That was my original reason for looking at spray foam in the first place. Some people here have alluded to a beam running the whole width of the structure.... some pics would be great.

theoldwizard1 said:
Yes, SIPs cost more than stick built, but do they cost more than fully insulated stick built ! I have never seen a documented cost analysis either way.

OP did state that time was somewhat of an issue.

I'll explain more about this. I have an existing 22x24 that I am completely getting rid of. The project started with a thought that I could "renovate" it out to a larger size. I've since abandoned that idea in favour of a complete replacement (see my sig thread for that journey). So on the time side, I need to get the old garage out, and the new garage in before the snow flies. It gives me about 5 months to do it between May and October. So that is the timeframe.

This sounds like plenty of time, however I'm gone for most of May for work, and August is summer holidays. So I'm really down to 3 months. Throughout that time I need a place to park the 4 vehicles that would otherwise sit in this garage. So being able to erect a wall that is instantly insulated and sheathed is a fascinating idea for me. Spray foam is good too. Batt and vapour barrier is extremely slow - especially up in the loft area.

As for $$$, my budget is $35k. I can go higher, but every dollar I spend over that comes out of my furnishing money. So no lift....

jvitez said:
I have lots of life insurance, but my wife says I'm still worth more alive. But if I kill myself working so much at least I'll leave a rich widow. Never thought how her next husband will like the garage.

Now that is hilarious!

rancherbill · Dec 31, 2014

JohnnieMo said:
Thanks Bill. However I completely disagree with your point about spray foam in Canada. Mike Holmes does almost 100% of his shows in Canada and spray foam is the only thing he uses. You can get a far higher R rating with foam than with batt. I also have friends who just finished new builds with spray foam. I would agree that its not the norm yet, but its not unusual.

I'm sunk!

It is hard to argue with "Mr Oh look there's a drip from the tap, let's tear the west wall of the house down because there might be mold'. :bounce:

Seriously, you have to do a heat loss calculation and the get some quotes. You will need to know exact measurements for all walls, floors, windows, doors, roofs etc. There all Alberta furnace sizing heating calculators online.

I did our house 7 years ago. At that time I found it was 2" foam under the concrete, 2x6 walls with higher RSI fiberglass and 2" of foam on the exterior, triple glazed windows, and R60 in the attic.

The garage was the area that was special. Doors as a percentage of wall area was large. Man doors are not high RSI and neither are the big doors. In addition, the big doors are hard to seal and when you really look at them, all around the edge your barrier to the outside is just the gasket material which has an R value of .01!!!

The other thing that heating calc will show you is that there is substantial decresign returns with lower temperature differentials. In my garage I keep the temp from 8-11 (45-51f) in the winter. It is very pleasant with a shop coat, or light sweater. If I want I can make it higher if necessary, but, I looked at the energy necessary to keep it at 21 (70f) and it was expensive.

A plan you have to plug into the calculator is this one from CMHC. It is for northern communities and they have substantially higher temperature differentials than we do in Calgary.

Do a plan like this, and put tons of money into the big doors and windows. That is where you save energy not on spray foam for the walls.

BTW, you don't have to use fancy blue studs for the framing either, just do the air barrier and exterior barrier correctly the first time.

JohnnieMo · Dec 31, 2014

Thanks Bill. Perhaps I misunderstood your point initially.

One of my initial queries is whether or not it makes sense to heavily insulate the walls and roof of a garage when there are such obvious holes (Ie. Doors). You are seemingly the first to say it doesn't make sense. I think I agree with you.

I like spray foam because it's quick to do, easy to put on the underside of the roof, and it leaves much of the wall cavity available for other things.

The big deal is that I need to get the garage water proof (Ie vapour barriered) by snowfall. If I do batt that means I need all the electrical, air lines, gas etc done beforehand. Spray foam means there is no rush.

Everything is a compromise between time and money ultimately.

I still like SIPS but more for expediency and 'uniqueness' more than for its inherent insulative value. That's just a bonus. Speaking of SIPs, how do you finish the interior? Can you just paint the OSB or is drywall still needed?

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DC73 · Dec 31, 2014

JohnnieMo said:
. . . One of my initial queries is whether or not it makes sense to heavily insulate the walls and roof of a garage when there are such obvious holes (Ie. Doors). . . .

New member. Been lurking for a few days and just came across your thread.

I don't think you'll regret insulating to the extent you've considered. The doors are not that big of an issue. You can get fairly well insulated garage doors and seals to keep cold air out. Unless you plan on keeping the doors open, they won't impact your temperature all that much due to thermal mass within the garage. For example, if you heat your garage to say, 60 degrees, all of the concrete, walls, fixtures, cars etc will also be at 60 degrees. Once you open a garage door, the cold air will replace your heated air to some extent but everything else will take much longer to cool down due to the thermal mass which means it also won't take long to heat the air back up.

A good authority on insulation, building construction and especially on vented vs non-vented attic space is Joe Lstiburek with Building Science Corporation. There is some great info on their website ( http://buildingscience.com/ ) and he has written several books including Builders Guides for every climate. It would be worth picking one up and reading. http://www.buildingsciencepress.com/Builders-Guides-C1.aspx

Good luck,

DC

Denwood · Dec 31, 2014

Yes, your garage has mass, but BTUs lost through the door are significant. My build thread has thermal images during and after foam installation. If you think the door is not an issue, check this pic of the outside of my shop at -5C. We also just finished a 9500 sq/ft building that cost less than my house to heat..and it has 10x14 overhead door in our shipping/receiving area.

These are a few thermal images from my build thread..I also posted a few Of the spray foamed ceiling before/after 5/8 drywall. The shop ceiling is a non-vented design so the soffits are all sealed with foam. My older house has the attic floor spray foamed to air seal the plaster/lathe/balloon framing with R60 cellulose blown over that.

JohnnieMo · Jan 1, 2015

DC73 said:
New member. Been lurking for a few days and just came across your thread.

I don't think you'll regret insulating to the extent you've considered. The doors are not that big of an issue. You can get fairly well insulated garage doors and seals to keep cold air out. Unless you plan on keeping the doors open, they won't impact your temperature all that much due to thermal mass within the garage. For example, if you heat your garage to say, 60 degrees, all of the concrete, walls, fixtures, cars etc will also be at 60 degrees. Once you open a garage door, the cold air will replace your heated air to some extent but everything else will take much longer to cool down due to the thermal mass which means it also won't take long to heat the air back up.

A good authority on insulation, building construction and especially on vented vs non-vented attic space is Joe Lstiburek with Building Science Corporation. There is some great info on their website ( http://buildingscience.com/ ) and he has written several books including Builders Guides for every climate. It would be worth picking one up and reading. http://www.buildingsciencepress.com/Builders-Guides-C1.aspx

Good luck,

DC

Here is a relevant abstract from the site you listed:

Application of Spray Foam Insulation Under Plywood and OSB Roof Sheathing Building America Report - 1312 September 2013 Aaron Grin, Jonathan Smegal and Joseph Lstiburek

Abstract:
Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. There have been isolated moisture related incidents that raise potential concerns about the overall hygrothermal performance of these systems. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed-cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate

Basically SPF on the underside of roof sheathing is safe.

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OldNeons · Jan 1, 2015

Whatever you do, I'd definitely go with the radiant floor heat! Good luck!

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