Raising the roof

[Dr Stan]

I'm kicking myself as I knew when I built my 24 X 48 shop it should have 12ft walls, but instead made them 8ft. Trying to save a buck.

So now I'm in the process of raising the roof four feet.

I've designed a scissor lift using structural grade 4 X 4's and have the remainder of the hardware arriving tomorrow. This will allow me to raise the roof in three 16ft sections.

When I first built my shop with the 8ft walls I installed the trusses without a ceiling so I could use them for storage. However I insulated the underside of the roof with fiberglass batting. Being the safety nazi I am I was concerned with welding sparks reaching the kraft paper and igniting. I'm removing said tiles and they will not go back up. I'm still somewhat concerned with welding sparks reaching the ceiling, but realize the chance is quite low.

Is there something one could recommend to protect the underside of the insulation? I researched Tyvek and discovered it has a class 1 fire rating just like typical clothing. They also have a fire retardant version which I assume is much more expensive.

Am I over thinking this? Should I install a ceiling and store the material on the added 4ft height of the walls? Should I cover the underside of the insulation with light weight fire resistant canvas? Just cover the area above my welding table?

I'm also seriously considering buying/building a large hood with forced ventilation above my welding bench. Would this effectively eliminate my welding spark/fire issue?

Or am I still over thinking/being a super safety nazi?

Thanks in advance.

 

[Firebrick43]

Every one around here that has put up a white metal ceiling, sometime begrudgingly, stated after just a short time, it was the best upgrade. The light reflection and therefore improved vision is awesome.

Did a neighbors shop last winter 30x30 for around 700 dollars. He used an attic stairway so he could still access the attic.

 

[RVDan]

So drywall is not an option?

 

[GYPSY400]

Insulate the roof (properly for your area) and install a ceiling. White vinyl siding is also an option..then you can build shelving around the perimeter from 8 to 12 ft... even a 2ft wide shelf up 8ft high by 24ft long will give lots of square footage for the wife's junk!

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[Falcon67]

My old shop was 20x24, 8' ceiling with kraft backed insulation exposed on the walls and ceiling. Welding, grinding, torch work, etc. 13 years, not even a scorch mark on the kraft paper. If you really have to have something, light weight drywall would be about the most I'd do. Or 1/4" OSB. Fire! Fire! Wait, I use a sheet of OSB for setting off fireworks and no fire. I also weld, grind, etc surrounded by OSB.

 

[73RR]

The metal ceiling panels are light-weight and very light reflective but they are also very sound reflective.
OSB is fairly light weight and will need several coats of paint or it will **** up a lot of light...paint it before you install it... Does help some with noise.
Sheetrock is just plain heavy. The problem of using 1/4 or 3/8 is that of truss spacing. ½" will span 24" no-problem, the thinner stuff will sag and if you are in a humid region then it will happen sooner than later. Sheetrock also should be painted as the paper will darken/yellow with age.

 

[6768rogues]

How are you extending the sidewalls without creating a hinge point where the new and old walls intersect?

 

[DCarr2]

OSB doesnt needs a lot of paint to make it work, just the proper paint to make it work...


I found out while getting quotes for spray foam that sherwin williams makes a moisute barrier paint.

Not sure the retail on it, but I used 20 gallons on my shop... was $130 a 5. x 4


sprayed that on, then went with the cheapest crappiest enamel SW offers, called masterhide...semi gloss white. 2 coats (sprayed) and Im good to go. On the bottom 10' I did 2 coats of the moisture barrier and 3 coats of the enamel

 

[JohnnieMo]

I raised my entire garage to get more headroom. Thread is here:

http://www.garagejournal.com/forum/showthread.php?t=308011

I know my approach is different but there could be some info for you.

 

[Dr Stan]

How are you extending the sidewalls without creating a hinge point where the new and old walls intersect?

That's a good point and I have it covered. Technically there will be a hinge point, but I'm not simply nailing the extension of the wall to the existing toe plate. It will have 1/4" carriage bolts holding them together most likely every 2 ft roughly centered between the trusses along with construction adhesive.

Another thought is to run steel cables from the new top plate through the old top plate using forged eye bolts & turnbuckles. I have several from a safety net installation where I was employed. I believe everything is 5/16" in diameter.

There will be a new toe plate along with hurricane ties. I plan to simply cut the existing ones as it will be easier than trying to remove them.

 

[Dr Stan]

So drywall is not an option?

It's a possibility, but one I'd like to circumvent.

 

[Dr Stan]

I raised my entire garage to get more headroom. Thread is here:

http://www.garagejournal.com/forum/showthread.php?t=308011

I know my approach is different but there could be some info for you.

That is certainly worth considering. BTW, good job.

 

[ard]

That's a good point and I have it covered. Technically there will be a hinge point, but I'm not simply nailing the extension of the wall to the existing toe plate. It will have 1/4" carriage bolts holding them together most likely every 2 ft roughly centered between the trusses along with construction adhesive.

Another thought is to run steel cables from the new top plate through the old top plate using forged eye bolts & turnbuckles. I have several from a safety net installation where I was employed. I believe everything is 5/16" in diameter.

There will be a new toe plate along with hurricane ties. I plan to simply cut the existing ones as it will be easier than trying to remove them.

No permit, right?


Be interested to have an engineer opine here.

Basically look at a 2x4 wall, the thing that resists bending is a 2x4 on the 4" edge. Gluing and bolting the top and bottom plates do not provide this same resistance. Toe nails, hails through the plate, even anchors will not provide this same rigidity. IMO it isnt that they come 'up' or 'off', it is the resistance to hinging (as pointed out above)

If the walls were sheathed with plywood, with 8ft plywood sections overlapping the 4 foot addition, that would be 'having it covered'. Better on both sides. And even then Id want an engineer to review.... IMO

 

[Dr Stan]

If the walls were sheathed with plywood, with 8ft plywood sections overlapping the 4 foot addition, that would be 'having it covered'. Better on both sides. And even then Id want an engineer to review.... IMO

What's a permit?

BTW, I'm only doing a hail damage repair.

You point re plywood is very good. On the current walls I used OSB and metal reinforcement on the corners. Plywood it will be along with more metal reinforcements at the corners.

I've also been kicking around some ideas. I could run 1/2" 1018 rods from the top of the addition down to the anchor bolts using coupling nuts to tie everything together. No more hinge.

I can access the anchor bolts by cutting the inside MDF a foot above the floor using my circular trim saw, or removing some of the inside panels.

 

[ard]

I've also been kicking around some ideas. I could run 1/2" 1018 rods from the top of the addition down to the anchor bolts using coupling nuts to tie everything together. No more hinge..

I thought about that, but still a hinge. The wall wont 'come apart' and the roof would still be tied to the foundation, but that wall WILL be less rigid.

The problem is that there are certain standard building practices, and if you follow them the resulting construction will meet the standards. If you do not follow them, then a whole slew of considerations will need to be evaluated.


In this case, you tie the bottom plate down, you nail the studs at top and bottom plate, you user hurricane ties. All good. The roof gets wind loaded, the ties transfer to the walls, the walls resist shear and bending- all good.

Now put a hinge in the wall. WHICH ISSUES NEED TO BE ADDRESSED? You can stiffen the hinge (and placing it in tension with a rod is not a 100% fix- it just means it wont pull UP, but it can fold over...) or you can evaluate 'what was that wall doing, in terms of the whole structure. Ive had walls than needed 3/4 ply nailed every 4 inches both sides to develop adequate shear (with 3/4" rods from foundation bolts up through this panel to the second floor above- and I am not in earthquake country,) Perhaps the 'solution' for your structure is 'each corner gets sistered studs from plate to plate with shear panels 48 inches from each corner. Plus one 96 inch section at mid span on the 48 ft wall'. Dunno.

Once you depart from the standard construction methods, you are somewhat in the woods....

 

[Falcon67]

>OSB doesnt needs a lot of paint to make it work, just the proper paint to make it work...
Or don't paint it at all.

 

[Orionrising]

Studs are cheap... Pull the top plate and sister in full length studs to the top... No hinge.... Will mess with insulation widths through.

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[JohnnieMo]

From my experience, no matter how well you fasten the lower wall segments to the upper wall segments, you will require some full length studs to stiffen the wall. I ended up sistering studs about every third one. (and some people are still crying for my head on a stick after that) I am only basing this on my personal experience. Otherwise the whole building is unstable.

New exterior sheathing will help that too. I don't think the cables you are suggesting will do anyything to solidify the hinge point.

An idea I had, that I didn't implement, would be to create a small triangle truss that goes above the bottom wall and fastens to the roof. This would delete your hinge point and be very strong. You could then use the resulting cavity to put in lights. (I've seen guys do this before quite effectively.)

Here is my crappy drawing. The red is the part I'm referring to. This approach would work better on a 2 foot lift, and not as well on a 4 foot lift.

 

[Dr Stan]

OK everyone I will not take any shortcuts and will sister in studs from the sill plate to the new top plate. Just have to determine the spacing (32" ?) & just how this will be done.

Can trim the insulation as necessary.

 

[Falcon67]

If I read that right, your 4x4 supports are on 32" centers. Then I'd sister the 4xs from top plate to sole plate and add one at 16" OC.

 

[Dr Stan]

If I read that right, your 4x4 supports are on 32" centers. Then I'd sister the 4xs from top plate to sole plate and add one at 16" OC.

That's what I was thinking. However I decided to "be nice" and visit Planning & Zoning today. I need to have the power disconnected at either the weather head or the pole to be able to keep the weather head above the roof. Then I'll have to install longer leads & about 4ft additional conduit from the weather head to the meter.

I suspect I'll need a new building permit even though there was no height stipulation when I first built my shop. The last thing I want is grief from P&Z and they have been very helpful & nice to me in the past.

 

[JohnnieMo]

That's what I was thinking. However I decided to "be nice" and visit Planning & Zoning today. I need to have the power disconnected at either the weather head or the pole to be able to keep the weather head above the roof. Then I'll have to install longer leads & about 4ft additional conduit from the weather head to the meter.

I suspect I'll need a new building permit even though there was no height stipulation when I first built my shop. The last thing I want is grief from P&Z and they have been very helpful & nice to me in the past.

Good point. In Calgary there is a 15' max on supplemental structures as well as a 9'10" eave height max. If you exceed either you require a development permit, which takes 6 months. I ended up doing such a permit because of other overages, but it never hurts to be careful on these things.

 

[Dr Stan]

Just returned from Planning & Zoning. Started the application process for a building permit & an electrical permit. Total fees comes to $61.00 and absolutely no hassle from P&Z. Nice and very helpful guy as a matter of fact.

Also its not necessary to file a legal notice in the paper as I'm not modifying the foot print. When I built my shop the newspaper charged over $500 for the notice and I didn't even get a kiss.