Installing a Wall between 3rd Car Garage

[soonerbrink]

I have a workshop area setup in my 3rd car garage, and have cars in the 2 car portion. I am considering adding a door and a wall between the two areas, and insulating the garage.

The main reason is to reduce temperature fluctuations hot with cars in the garage during the summer, and cold in the winter. HVAC will follow shortly after this phase.

I probably won't be tackling all of this project on my own, and may be getting quotes from contractors. Rather than having them tell me what I need, I would like to get input on here, so I can tell them what I need.

What type of framing to use on the new wall?
What type of insulation on the new wall?
Probably will want a power outlet on the new wall. Is this worth the hassle?
The base of the existing walls in the garage are concrete from the foundation. What do I put along the base of the new wall to prevent water from being absorbed from melting snow that falls off of cars?
What is the best insulation for my open attic above?
What is the best way to put insulation in existing garage walls that already have drywall, are already painted, and have items hung on them?

I did a quick search and surprisingly couldn't find someone that already did this. If you there is a post with this info... please share!

 

[astroracer]

This is easy to do and can be done in a weekend if you hit it hard. Use a pressure treated 2 x 4 as a sill plate. Use construction adhesive and a power nailer to install it. Use regular 2 x 4's for the studs. 24" O.C. will work well. Depending on rafter direction you may need to install some short girts between rafters to attach the header too. Again, use a regular 2 x 4 for this. Framing in the door should follow basic construction rules. Running wiring should also follow code. Put outlets every 4 or 6' on BOTH sides of the wall.
Fiberglass batt insulation will do the job as well as anything and it is pretty cheap.
Mark

 

[Bluedodge]

^^^ What astroracer just said.

Under your PT sill plate, use foundation seal tape (rubbery type, not the blue foam type). You will also want to hang your sheetrock with an approx 1/2" or 3/4" gap from the floor to slow water migration. For baseboard, use PVC trim designed for exterior applications. Water and snow run-off won't damage it.

 

[thool]

I would consider steel studs on 16 centers. They are perfectly straight and very easy to work with.

 

[soonerbrink]

Thanks for the feedback!!

Any suggestions on best way to insulate the existing walls that already have drywall up?

 

[kbs2244]

I would consider a heavy curtein instead of a permenet wall.
Maybe made from area rugs.
Much cheaper and easier.
And you would be able to move it out of the way for a big project that keeps the cars outside.

 

[soonerbrink]

That's an idea, but I would be curious to know how well it insulates compared to a traditional insulated wall.

 

[cowboy73]

Thanks for the feedback!!

Any suggestions on best way to insulate the existing walls that already have drywall up?

The easiest way would be blown insulation. You would drill two holes between the studs to blow in the insulation. One hole about half way up and the other one near the top. Of course you would have a lot of holes to patch in the drywall but it could be done.

 

[soonerbrink]

The easiest way would be blown insulation. You would drill two holes between the studs to blow in the insulation. One hole about half way up and the other one near the top. Of course you would have a lot of holes to patch in the drywall but it could be done.

Could I just put both holes near the top and then put some type of border or trim over all the holes?

 

[matt_i]

I did it and wished I didn't. Ended up taking down the framing and drywall one side. The reason was the garage was so small the car doors couldn't open with the wall in place. Had the same issues of large temp rise when the car(s) pull in and also trying to stabilize humidity. I knew of this issue and predicted it, but well, sometimes you don't win these things.

 

[soonerbrink]

I did it and wished I didn't. Ended up taking down the framing and drywall one side. The reason was the garage was so small the car doors couldn't open with the wall in place. Had the same issues of large temp rise when the car(s) pull in and also trying to stabilize humidity. I knew of this issue and predicted it, but well, sometimes you don't win these things.

Did you split a 3 car, or split a 2 car garage? I am not planning on putting a car in the third bay ... so if I wall it off, its just like a regular 2 car. I already have stuff in the way where the doors would open to the wall..... so i am already familiar with the door clearance.Thanks!

 

[soonerbrink]

For the existing finished exterior wall, can I put two holes at the top section between the studs to blow in insulation, and then put a long piece of trim over the line of holes?
I assume this would be much easier than trying to make a line of drywall hole repair visually appealing by repairing each one individually?

 

[kd7gab]

For the existing finished exterior wall, can I put two holes at the top section between the studs to blow in insulation, and then put a long piece of trim over the line of holes?
I assume this would be much easier than trying to make a line of drywall hole repair visually appealing by repairing each one individually?

Lookup 'dense pack cellulose', that method will be the best option for blowing into existing walls. Additionally, you will need only one hole (unless you have fire breaks in the wall cavities). Once you've blown the insulation in, you would just need to patch the holes.

I used this method in my parent's place. Worked very well and cut their energy bills in half. They saw a return on the cost in less than a year!

~Jon

 

[finn]

I did it and wished I didn't. Ended up taking down the framing and drywall one side. The reason was the garage was so small the car doors couldn't open with the wall in place. Had the same issues of large temp rise when the car(s) pull in and also trying to stabilize humidity. I knew of this issue and predicted it, but well, sometimes you don't win these things.

I predict that the op will fall into the same trap.

Many 3 car garages are simply too narrow to be useful if chopped up with a dividing wall.

Unless the garage is 36' wide, I'd forget the idea of adding a wall.

 

[soonerbrink]

Lookup 'dense pack cellulose', that method will be the best option for blowing into existing walls. Additionally, you will need only one hole (unless you have fire breaks in the wall cavities). Once you've blown the insulation in, you would just need to patch the holes.

I used this method in my parent's place. Worked very well and cut their energy bills in half. They saw a return on the cost in less than a year!

~Jon

Any idea of the cost difference for 1 wall?

Based on reading an article, it looks like it wouldn't be as beneficial on a newer home garage wall that has brick on the exterior.

I would be putting blow insulation in the attic above, so this would be another cost for two types of insulation installed.

Thanks!

 

[ratdoggy]

I would consider steel studs on 16 centers. They are perfectly straight and very easy to work with.

Me too...That's how I did my basement

 

[Voi]

I did it and wished I didn't.

I predict that the op will fall into the same trap.

Many 3 car garages are simply too narrow to be useful if chopped up with a dividing wall.

Unless the garage is 36' wide, I'd forget the idea of adding a wall.

My garage is 38' wide on the inside and I would love to tear down our dividing wall. Our third stall was an addition by a previous owner and the dividing wall is a very thick poured concrete wall since the garage was/is mostly below grade. They took out about 7' of the wall for a walkway in between but that's not enough for door swing for our vehicles.

One of these days I'm going to get a structural engineer over here and see how much of that wall I can remove.

 

[soonerbrink]

My garage is 38' wide on the inside and I would love to tear down our dividing wall. Our third stall was an addition by a previous owner and the dividing wall is a very thick poured concrete wall since the garage was/is mostly below grade. They took out about 7' of the wall for a walkway in between but that's not enough for door swing for our vehicles.

One of these days I'm going to get a structural engineer over here and see how much of that wall I can remove.

Perhaps I need to consider another option before installing the wall...
It's not very pleasant working out there most of the year. Just want to keep the cars separated from the work area to prevent 105degree temps inside during the summer, and be able to prevent 42 degree temps in the winter... or even colder when the door opens. Keep in mind I was planning on adding some type of heating/cooling to go with the insulation.

I am usually out there each day of the year working on projects or playing pinball. Right now, there is plenty of room for the cars... but that could change if we get larger vehicles down the road.

Thanks for all the input!

 

[Voi]

Perhaps I need to consider another option before installing the wall...

Maybe some sort of temporary wall to see how you like it?

I walled off my shop from the rest of my garage with a 17' curtain of Reflectix insulation for an entire winter. Worked better than expected and was only heated with a 1500 watt electric heater. To be fair, I got the stuff for nearly free.

But before you go out and buy rolls of the stuff maybe give some thought as to what you could build a temporary wall from that will have use to you regardless of whether you build the wall in the future or not?

 

[wkearney99]

Any suggestions on best way to insulate the existing walls that already have drywall up?

Drywall is relatively cheap, rip it down and re-insulate it properly. You'll be having other drywall work done for the new wall anyway.

It'd likely be a wash versus cutting holes and trying to blow insulation in there. There's often firebreak or other blocking in-between the studs. For which you'd have to cut another hole and spend more time trying to fill it.

Just bear in mind that if you want to use this as a conditioned space you're going to have to figure out a way to get the HVAC system to support it. Yours may or may not (likely not) have enough capacity to handle the added load. That and you'd have to run both feed and a return for it. Bearing in mind, however, you REALLY want to avoid having garage/shop fumes being recirculated through the rest of your house. That being the case then you'd probably need to go with a mini-split kind of setup. They're a good solution for something like this.

 

[langss]

I just bought a new house with a three car Garage, thinking that I could use the house air and heat, and then I read on here(GJ) that the Garage must be separate from the main part of the house for fire reasons, so no using the house air or heat for the Garage. We used these where I worked before I retired. http://www.goffscurtainwalls.com/ Indoor they would last forever. Outdoor not so much.

 

[pmiranda]

I think OP is planning to completely separate one bay from the garage proper, so if done correctly with fire-rated drywall and fireblock at the top and edges he could then link the AC from the house, but it's usually easier to add on a DIY minisplit so you don't lose pressure/capacity in the house and it's easy to undo later if you want the garage back to full size.