New, first, hopefully long term garage

[Navydoc]

Good morning,

Long time lurker here at Garage Journal. My wife and I just built our first home and the deal was that she got a bigger kitchen and I got a garage. Well we have lived in the house for almost a year, with a kitchen that the family is stepping on each other in, and I am finally able to start the garage this summer. I know enough about construction to get myself in trouble but with the wealth of information on here thought I could educate myself more. The preliminary plans were finished the other day and I was looking for suggestions of what you would do different better etc. The second floor is going to be a woodworking shop. I got the idea for the trap door and hoist from someone one this forum. I apologize that I don't remember the name to give them proper credit.
Walls are 2X6. Plan to spray foam at least the first 2" if not 4".
I still haven't figured out how to heat and cool the place yet. I am leaning toward in floor heat but do not know how that would play out for the second floor. The main purpose is to keep condensation down so that the tools do not rust.
Foundation will be pored.
I really appreciate the help in advance. My hope is that I can keep this thread or another going once I start building.

 

[matt_i]

Something is wrong with the man-door width and the radius it swings thru.

My experiences with attics are they are tough to keep comfortable year-round, minimal insulation in winter and plenty of sun-load in the summer. But its good space to use.

The potential R-value from 2" of spray foam seems low at ~R3.7/inch. I used Roxul which is R23 in the same 5.5 inch cavity. Not sure which is a better deal financially as I haven't run the numbers.

Best formula for keeping rust at bay is a three pronged approach - keep space closed as much as possible creating microclimate, keep air stirring constantly in all weather with a ceiling fan on lowest speed and use a dehumidifier to concentrate and remove moisture. Don't have to run the dehumidifier on constant run, some have setpoints that kick on and off. I use Boeshield T-9 in the woodworking area of my basement as an additional protector that doesn't adversely affect the wood.

In my shop build, I wish I would have insulated the attic floor (garage ceiling) before putting down the 3/4" T+G plywood. I drywalled the ceiling and the long narrow cavity is tough to get correctly filled with loose fill cellulose. And I have discovered the same issue of voids in another part of the shop which was existing and I didn't build. However had I done the construction sequence differently, added bracing to the trusses when I was framing, then done the drywall ceiling when the building was enclosed, then insulated, then finally installed the plywood decking it would have been easier and better. Alternatively I could have screwed in all the plywood and taken out sections later. But I was mentally geared into sawing stuff and hammering nails and it all ended up going in shortly after the roof was finished.

 

[HoosierBuddy]

I have a 2 story garage with floor heat upstairs and down. However, my upstairs is finished space (bonus room/family room).

I accomplish it with a natural gas fired modulating wall boiler mounted in the garage level (vented out the side wall) with zones for the garage itself and the upstairs.

The garage heat is excellent using an insulated slab.

The heat upstairs is marginal. While you'll find many places online that indicate you can loop pex under the subfloor and get decent heat that way....in practice it is not very effective, and this is even with 4" fiberglass batts between the pex loops and the ceiling of my garage. If I had that part to do over, I would definitely buy one of the subfloor systems that incorporates the pex loops right into the subfloor (OR) put the pex loops on top of the subfloor and pour lite-crete over that to create a good "radiator" to heat the upstairs.

In my case I had to add a secondary gas heater upstairs on a second t-stat set a bit lower than the radiant heat. It kicks on a few times a day during colder days when the radiant can't keep up.

The issue really is that the water coming back from those upstairs loops is too warm returning. I'm not getting enough heat out of the water to warm the upstairs. With lite-crete especially, you would be able to get so much better heat transfer out of the pex and into the floor that it would be (estimated) 3 to 10 times more effective.

If putting pex under the subfloor is the only option then those metal plates designed for that purpose do work better than just looping the pex over insulation. In another area of the house we added those the heat went from "poor" to "marginal"...but where we have the loops in concrete in the garage the heat is "excellent".

Phil

p.s. As this is a detached building, I should point out that in-floor radiant is not a good solution for part-time heating. If you are going to leave the barn cold until you plan to go out there and spend time, don't use it. Use a forced air system instead so you won't have to worry about freezing, and can design with extra capacity for quick warm up when you are using it.

 

[Navydoc]

Matt, thanks for the insight
I neglected to post that I was going to use batt insulation over the spray foam. I used 4” of spray foam in the house with batt insulation over and achieved pretty good R value. It is very comfortable in the house. I hope accomplish the same with the garage.
I use Boeshiled also.
Definitely will plan on putting a few fans on the upstairs ceiling.


Hoosier:
It is good to hear real world experience with 2 nd floor in floor heat.

For forced hot air would that be one trunk line for each floor so that I could seperate the zones?

 

[HoosierBuddy]

I'd need a bit more information:

1. What are your goals as far as heating: 24X7X all winter or just during times when you are going to be working out there.
2. What fuel sources do you have available: Electricity? Natural Gas? Propane?
3. Do you forsee a need for AC? Right away? Might want sometime down the road? Niether?

Phil

 

[Navydoc]

Hoosier,
I will be able to have natural gas and of course electricity run to the garage.
The garage will be kept at a constant temp, let’s say 50-60 degrees, then increased when I want to go out and work. God willing I will be able to spend more and more time out there each year.
As it hits 90+ here today AC seems like a much better idea.
Scott

 

[Stuart in MN]

In floor heat is great, but is best for keeping a constant temperature - turning it up when you want to go out there will take a while and isn't very efficient. You may want to include auxiliary heaters for that purpose, but having said that in floor heat can be more comfortable at a lower temperature setting than forced air heating.

What kind of woodworking projects will you have, and what kinds of tools? Hauling a big Unisaw table saw up the stairs won't be much fun, the same with 4x8 sheets of plywood. You may want to include some sort of hoist and access door. (edit - I just looked closer, and you are showing a trap door so never mind. Do make sure it's big enough to move what you need.)