I am in the process of about a 750 sq ft remodel. Home was built in 1950's. It has hardwood throughout. working from bottom up, concrete slab (3" above grade), roof felt, 2 x 4 (not treated) 24" OC, 3/4" oak hardwood. Southeast, coastal.
Because I am trying to match existing rooms and it appears to be an acceptable method (60 years), I was planning to keep with the sleeper method. I have read the the NOFMA recommendations and many people have referenced it but I have not seen any practical experience posts.
My plan is to get the sleeper system in and then hire the flooring installer to put the strips down. My goal is to have the sleeper system so it is very easy on installer. I was going to strictly follow NOFMA recommendations, but have questions.
1. Concrete prep. I have 3 different pours of concrete, some flatter than others. Can I adjust as I lay sleepers with shims (plastic), thicker mastic, etc...? My fall back is to mill the sleepers.
2. Sleepers installed in cold asphalt mastic. Is there a substitute? Every product that I can find that meets this definition is high solvent and exterior use only. Is this really needed with pressure treated lumber these days.
3. I would call the lumber flat but it will have small variations, twists, bow, board thicknesses, etc. 1/8" max. I can make the finished surface with just about no variations but very time consuming. I can meet the 3/16" over 10' spec but if I lay the next sleeper and it is 1/16" higher is that a big deal.
4. Sleepers installed 12" OC 4' long. Attaching with 2.5" ramguard nails every 24" (3 per 4' board)
5. From here it is up to the floor installer. I will request stainless steel nails/staples for PT sleepers. Is this common, unreasonable??
6. Is there a better way? I have to make up 2 1/4" to match existing flooring.

At this point my biggest hurdle is the asphalt mastic
Thanks for the help and I look forward to responses.

Will

Will I have seen this challenge before as we all know having a flat surface is so much easer to work with. I wouldyou highley recommend 12/15 mil plastic due to moisture out looking at project and taking the information you have provided . I would cut sleeper system to guarantee evenest throughout floor especially if your using prefinish product it is much more unforgiven then a unfinished product. Wishing you best of luck wentzwood

If the existing is mastic then I would stick with it, that method is tried and true. The smell dissipates somewhat and is buried anyway. You could go with something like MVP4 but I would call and ask them first.

MVP4 seems like a suitable product. The previous and exist floor is just roof felt between slab and sleepers.
What is the purpose of the asphalt mastic? Moisture control or adhesion? To me, they are pressure treated sleepers and there are methods of floating floors. Once the floor strips are installed with poly between floor and sleepers, it should make the fastening and waterproofing the sleepers a lot less critical. What am I missing?

Not sure if pressure treated sleepers are recommended, they hold more moisture then regular wood. Mastic is for moisture control and just roofing felt does not do as good of a job over concrete, especially if the concrete has a high mver.

I have the NOFMA sleeper doc here somewhere but I remember something about multiple layers of mastic and six mil plastic. I'm thinking one layer of each would suffice, or one layer of MVP4 and plastic just to be sure. Then fasten down the sleepers with tapcons.