Garage conversion

  • Advertise with us

« back to Woodworking Skill Share forum

Forum topic by bnisimov posted 05-22-2019 03:35 AM 601 views 0 times favorited 13 replies Add to Favorites Watch
View bnisimov's profile


16 posts in 1755 days

05-22-2019 03:35 AM

Topic tags/keywords: garage conversion

I’m trying to convert an attached garage to a bedroom we live in NY. There is a heated basement underneath the concrete slab.
Few questions.
1. what type of flooring should I consider. engineered hardwood tongue and groove the floating style or laminate?
2. the garage floor is not even. I was considering using a leveling mix but then got an idea of using 2 by 4 and just level the floor and add plywood over and then the flooring.
3. do I need a moister protection? since the garage does not get flooded and there is basement underneath of the garage. But i would imagine the concrete slab does have different temperature than the rest of the house.
4. i was also considering using some type of insulation in the floors. What should do you recommend?
5. maybe there is another forum where I can ask my questions?


13 replies so far

View LittleShaver's profile


676 posts in 1395 days

#1 posted 05-22-2019 12:40 PM

While I’m sure there are lots of folks on this site who can answer your question, I’d also try over at

-- Sawdust Maker

View ocean's profile


208 posts in 1609 days

#2 posted 05-22-2019 12:57 PM

You need to know how out of level your over all floor is. Focus on the the leveling first. A little don’t worry, a lot you will need some leveling compound applied to slab. You will get creaking sounds if you do not get it leveled properly. After that an under layment in most cases will add padding and a vapor barrier in one. You don’t say where you are. Climate will make your choice of insulation for you. Cold climate on concert slab means more insulation, warm simple underlayment will do. Hardwood is always the best, but laminate is cheaper.

-- Bob, FL Keys

View bnisimov's profile


16 posts in 1755 days

#3 posted 05-23-2019 03:39 AM

Hi, thank you for your reply.

I live in NYC.

1. When you say under laymen – can you give an example? but i would guess it depends on a manufacturer of hardwood or the laminate product.

2. wouldn’t i need to build floor up where the insulation would sit?

3. what type of insulation would you recommend?

Thanks a lot

View Horus's profile


60 posts in 444 days

#4 posted 05-23-2019 04:53 AM

Take a look at self leveling cement to level the floor. With heated living space below, you may not need a vapor barrier, but that’s inexpensive and easy to install – just some plastic sheeting or more expensive you could use tyvek.

With heated space below, you shouldnt need to insulate the floor. However, you’ll want to put some kind of subfloor in, unless your tiling the space – then I’d opt for in-floor heating (you can do that before the self-leveling cement to imbed it). Most garages aren’t heated well, so you’ll need to do something, kind of a two birds thing. If you heating the rest of the house with a boiler, you could tie into that system, if it’s big enough. Otherwise electric would work, but be more expensive to run. If you plan to run forced air, again check capacity of existing furnace, the inspector will…

Oh, that’s tight the question was about the floor… Take a look at the 2×2 ft subfloor panel, that are formed plastic down and plywood up, that may be adequate vapor barrier, check local codes. I like those panels, the floor isn’t so hard and sounds and feels more like living pace instead of a garage ( or basement).

Good luck.

Eschew obfuscation.


View Rich's profile (online now)


5621 posts in 1365 days

#5 posted 05-23-2019 04:56 AM

Eschew obfuscation.

- Horus

I eschew mastication.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

View MSquared's profile


1060 posts in 690 days

#6 posted 05-23-2019 05:42 AM

+1 Thanks, Horus! Saved me a lot of typing!! Thinking of doing same for my garage shop in (slow) progress.

bnisirov – I’m a good bit East of NYC, but But as a life-time NY’er, I’m assuming you’re in the boroughs. Double check that ‘slab’. Make sure it’s structural (Rebar, Structural Steel, Steel Columns, etc.). ‘Slabs’ technically sit on the grade or ground, with a porous stone base.

‘Sketchy’ renovations are commonplace in those locales. Great, solid houses, but for good or for bad, many people worked on and added onto their homes themselves. Because they knew how. Well, not everybody!! Take a very close look before you start!

-- Marty, Long Island, NY

View ScottM's profile


747 posts in 2922 days

#7 posted 05-23-2019 02:58 PM

Most garages are not built for occupancy, so I’m assuming that you have it permitted for this type of conversion?

View bnisimov's profile


16 posts in 1755 days

#8 posted 06-20-2019 03:11 AM

MSquared – there is a basement underneath of the garage. and what do you mean by structural if the garage is designed to hold up a car wouldn’t it be structural enough for a person to sleep in?

View MSquared's profile


1060 posts in 690 days

#9 posted 06-20-2019 05:34 AM


-- Marty, Long Island, NY

View MrRon's profile


5913 posts in 4019 days

#10 posted 06-20-2019 03:58 PM

Before you do anything, check with the county inspector. I know of some areas in the country that prohibit DIY construction. My brother-in-law was living in NJ and decided to put in a poured concrete walkway. The county inspector saw it during making his “rounds”, asked to see his permit (didn’t have one) and directed him to rip it all out. If he ignored that, the county would send a crew to rip it out and charge him for the removal. This was in a semi-rural area.

View MSquared's profile


1060 posts in 690 days

#11 posted 06-20-2019 04:16 PM

I was referring to the odd chance that someone dug out under the garage to add a room with home-spun reinforcement. Weirder things have happened. If it’s part of the original construction, fine then. I wish I had a space like that! :)

-- Marty, Long Island, NY

View tywalt's profile


104 posts in 940 days

#12 posted 06-20-2019 05:22 PM

Eschew obfuscation.

- Horus

I eschew mastication.

- Rich


-- Tyler - Central TX

View clin's profile


1113 posts in 1772 days

#13 posted 06-20-2019 11:24 PM

If the floor is in fact a concrete floor that is reinforced to support autos in the garage, it clearly is strong enough for anything you’d use it for short of an anvil warehouse.

Since the floor is not sitting on the ground and the space is heated below, it’s just a floor, though happens to be made of concrete. Now, it is possible moisture could come in from the edges of the concrete. I assume it contacts the ground somewhere. So there is some possibility of moisture getting in at the edge.

As has been said, might as well treat it like it is a slab on grade, and put moisture barriers as described for the type of flooring you are putting it.

I see no reason to build up the floor with 2×4 etc unless it is in fact not level. Some garages have a pronounced slope towards the garage door. You could easily have an inch or more drop it the floor. In that case you might want to use a true floor leveling compound which I imagine has some limit to how thick and can be spread. But even if generally level, it will NOT be flat. So you’ll still need to fill in the low spots.

Some engineered wood flooring is meant to go right on top of a slab, with appropriate moisture barrier and usually a thin sheet of foam for sound dampening.

If you are putting down a traditional wood floor, then plywood can be put down first to give you something to nail the floorboards to.

As others have said, best get a permit for this.

-- Clin

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics