[Brian Peters]

I've got a project coming up and have some questions. These folks have a sunroom which is built with concrete blocks, concrete floor and old aluminum storm windows. The floor is 4 inches lower than the adjacent kitchen floor. Plan is to open things up between the two, knock out the old windows and the block wall down to the level of the concrete floor, frame in a new wood framed wall to accommodate new windows and insulation , outside will get vinyl siding.

I want to raise the floor to the same level and they are wanting a hardwood floor so seems like a wood subfloor would be best, I'm just wondering about possible moisture issues. The concrete is probably twenty years old if that makes any difference.
I'm sure someone of you has run into something similar, just looking for some advice on this.

 

[griz]

You could always test the concrete for moisture content.

There are products that are an applied coating to the concrete to seal from moisture. They are usually expensive & labor intensive.

Another option is to put down a roll out vapor barrier, not a retarder, but a listed vapor barrier.

They work quite well, easy to install and price isn't bad.

 

[scottktmrider]

You might want to lay some polly or styphrom before you build the floor.And treated lumber if its going to be in contact with the concrete.

 

[ubcguy89]

I would put down a vapor barrier and frame sleepers

 

[EricBrancard]

I've done the double layer of 1/2" plywood over EPS foam as detailed in the Fine Homebuilding finished basement article from several years ago. That made for a pretty nice floor system.

 

[asgoodasdead]

like someone else said, vapor barrier and green lumber

 

[C2projects]

As it's been said vapor barrier and PT lumber, I'm not sure how large the span is but I have ran into several issues of either having to shim under my joists or cut them at an angle to account for the slope. Double check the level of the concrete it could vary depending on if there are a bunch of dips in the finish. Be prepared for every joist to be custom cut.

 

[Brian Peters]

Be prepared for every joist to be custom cut.

I am expecting that.

 

[hboogz]

Wanted to get something clear on this build. In the OP's post he mentioned that this sunroom is 4 inches lower than the adjacent kitchen. So, to build up to level from the poured concrete, you're suggesting something like this:

vapor barrier sheet across concrete.
mechanically fastening PT 2x4's across concrete acting as "joists"
lay osb/plywood on top of PT joists to prep for finish floor which will be level with adjacent kitchen floor.
start framing.

is that about right? Also, what are the choices for fastening the PT to the concrete? Ramset's? Is it standard practice to silicone the screwhead, since it's punctured through the vapor barrier ?

Thanks,

Harry.

 

[greg24k]

Knock it down what needs to be knocked down, have a step down finished nice in wood and use engineered glued hardwood floor or insulated floating floor. You will save so much work and you will make same money if not better and it will look real nice.

Also Depends on the budget, see if you can upgrade the job to radiant floor heat, nice trim package, etc. Jobs like this are good money makers if people are willing to spend.

Good luck:thumbsup:

 

[Bearded Wonder]

Last 2-3 jobs like that I just had my concrete guy come in and pour a cap up to the level I need. Works like a champ, and you aren't custom cutting joists or waterproofing or plywood or deflection etc.

Last couple cost me maybe $1000-$1500, but saved me more than that in labor and materials.

 

[hboogz]

Last 2-3 jobs like that I just had my concrete guy come in and pour a cap up to the level I need. Works like a champ, and you aren't custom cutting joists or waterproofing or plywood or deflection etc.

Last couple cost me maybe $1000-$1500, but saved me more than that in labor and materials.

That's cool. I hear a lot of the curing time in concrete ( 30 days, etc), I assume you laid an engineered or tiled above the concrete for the finish to account for expansion ? I'm guessing with the engineered you would still need a thin vapor barrier ?

 

[Bearded Wonder]

That's cool. I hear a lot of the curing time in concrete ( 30 days, etc), I assume you laid an engineered or tiled above the concrete for the finish to account for expansion ? I'm guessing with the engineered you would still need a thin vapor barrier ?

Yes. I did the concrete at the start of the projects and by the time it was ready to install flooring it had cured for almost 6 weeks. I'm not sure if there's a technical specified time to wait.

I've glued engineered wood flooring to a couple, and I've also done tile or carpet. Once it's poured and cured, I treat it the same as a new construction on a slab. Perhaps if there was a question about the moisture barrier under the original slab you could roll on some kind of waterproofing.

 

[SclafaniBuilder]

I just did this one. 2x4 joist.

 

[hboogz]

Yes. I did the concrete at the start of the projects and by the time it was ready to install flooring it had cured for almost 6 weeks. I'm not sure if there's a technical specified time to wait.

I've glued engineered wood flooring to a couple, and I've also done tile or carpet. Once it's poured and cured, I treat it the same as a new construction on a slab. Perhaps if there was a question about the moisture barrier under the original slab you could roll on some kind of waterproofing.

Awesome. Thanks for the reply!

I just did this one. 2x4 joist.

Very cool, this what I had pictured. What are those blocks on the corner of each row? Are those supports for radiant heating ?

 

[Brian Peters]

Awesome. Thanks for the reply!

Very cool, this what I had pictured. What are those blocks on the corner of each row? Are those supports for radiant heating ?

It looks to me like the blocks are fastened to the concrete and support the joists slightly above the floor , he 's got blocks fastened into the side of the joists at those locations.

 

[SclafaniBuilder]

It looks to me like the blocks are fastened to the concrete and support the joists slightly above the floor , he 's got blocks fastened into the side of the joists at those locations.

Correct. The floor is shimmed in spots as well. It's a solid floor. Had the whole apartments cdx sitting on it, never even flinched.

 

[hboogz]

Correct. The floor is shimmed in spots as well. It's a solid floor. Had the whole apartments cdx sitting on it, never even flinched.

Thanks! what did you use to fasten into the concrete?

 

[SclafaniBuilder]

Thanks! what did you use to fasten into the concrete?

3" pressure treated ramset with washer

 

[greg24k]

In any case I would stay away from using plastic over concrete slab.