Basement Sub-Floor Using Sleepers - Need Some Pointers

[BuilderML]

I am sure its to late now but it wouldn't hurt to have it turn up the wall a few inches.

 

[CHDinCT]

Just a few pic's of where things stand now. Didn't get too much done over the holidays due to being sick and then everything else going on. Just got the subflooring yesterday and hope to start putting that down soon. I need some finished square footage so I can move stuff around in order to finish putting down the Platon vapor barrier and sleepers on the other side. When you live in a house for over 25 years, you accumulate too much junk (that your wife won't let you throw out - ha)!

 

[MFWD]

Hello,
Since you only used 3/4" material as joists, how are you going to nail down hardwood flooring ? Or are you putting down a subfloor on top of the joists? Do they make short nails to fit hardwood flooring nailers and will short nails hold ok ? What is the spacing between the floor joists ? I saw places where you shimmed that set a good section of the joist up off the floor.....won't that cause a lot of deflection of the joist and cause the floor to be bouncy? Maybe you should [put in some more shims closer together to give more support. I'm not trying to bust your....just some observations and some questions. Good luck, I hope everything turns out fine !!!!

MFWD

 

[CHDinCT]

Hello,
Since you only used 3/4" material as joists, how are you going to nail down hardwood flooring ? Or are you putting down a subfloor on top of the joists? Do they make short nails to fit hardwood flooring nailers and will short nails hold ok ? What is the spacing between the floor joists ? I saw places where you shimmed that set a good section of the joist up off the floor.....won't that cause a lot of deflection of the joist and cause the floor to be bouncy? Maybe you should [put in some more shims closer together to give more support. I'm not trying to bust your....just some observations and some questions. Good luck, I hope everything turns out fine !!!!

MFWD

I'm putting 3/4" T&G OSB subflooring down for now, rated at 24" OC max, which is more than what my frame openning is. I've been adding shims and tapcons wherever I find defection. These pic's are in progress so you're not necessarily seeing the final set up. Also, I switched to black composite shims early on so you probably can't see all of them. Anyway, got some of the subflooring down and nice a solid so far. If necessary, I can come back and add a few tapcon's wherever necessary to eliminate any flex, but like I said, so far none needed.

By the way, when I was putting the insulation boards in I started cutting them with a utility knife and straight edge guide. That got tiring so I tried running a test piece through my table say. Wow, cut's nice and straight with no tearing except a little right at the end sometimes. Only issue is it leaves a lot of residue on the saw blade that doesn't want to come off easily. The blade is old so I'll just change it out once I'm done with the insulation.

 

[jel1988]

I use 2*2 dri core panels on a lot of basement jobs, we use both the insulated and plastic styles, depending on the situation. The leveling issue we ignore unless the floor is like a plowed field. The panels do accomodate a wide variety of slopes and humps. We install a separate 1/4" underlay for a vinyl floor finish and install carpet or laminate directly over the panels. We have tried the 5/8 T&G over the platoon membrane with equal final results, however it is time consuming. The panels cost more but the labour saving off sets any material costs. Does the floor have a vapour barrier underneath? A word to the wise, don't put plastic directly over the concrete (condensation will lead to mould), don't put any natural materials directly onto the concrete as mould will result. Good luck

 

[CHDinCT]

I use 2*2 dri core panels on a lot of basement jobs, we use both the insulated and plastic styles, depending on the situation. The leveling issue we ignore unless the floor is like a plowed field. The panels do accomodate a wide variety of slopes and humps. We install a separate 1/4" underlay for a vinyl floor finish and install carpet or laminate directly over the panels. We have tried the 5/8 T&G over the platoon membrane with equal final results, however it is time consuming. The panels cost more but the labour saving off sets any material costs. Does the floor have a vapour barrier underneath? A word to the wise, don't put plastic directly over the concrete (condensation will lead to mould), don't put any natural materials directly onto the concrete as mould will result. Good luck

I was originally going to use Dri Core until I realized how rough the leveling job was. I literally have ridges in a few spots. I would have skipped the sleepers if the floor was close to level, which would have saved a lot of time and expense. No, there's no vapor barrier under the slab if that's what you're asking. Also no plastic between the Platon and cement slab. No other organic material touching the floor. I've vac'ed up everything I could first and have tried to avoid even getting sawdust under the Platon. Best I can do. Neighbor across the street put plastic right on the slab and sleepers on top of that 20 years ago and he's said he's had no problems, but who knows what's under his subflooring at this point.

 

[MFWD]

Hello,
The last two pictures that you posted look really good. I'm glad that everything feels nice and solid. So, now what are you going to put on top of the subfloor.....hardwood flooring, tile, carpet ????? Looks like you'll have a nice floor whatever you choose !!!! Good luck !!!!

MFWD

 

[Danny C]

CHDinCT, I wish I had come across this thread in November when you started it! For what it’s worth, here is my :2cents:

Some basic facts:
- The soil under and around the bottom of your basement is at or near 100% RH all the time.
- The RH in your basement shouldn’t be any higher than 70-75% max.
- Moisture travels from areas of high moisture to areas of lower moisture
- Concrete is porous and allows moisture to pass through it.
- You have a moisture migration problem.
- 25 years is at or near the end of the life expectancy of your home’s weeping tile system.
- Weeping tile systems are designed to drain groundwater from around the bottom and beneath your foundation and not necessarily surface water.
- The groundwater table follows the natural contours of the land, including the top of hills. That is why you can have a dug well next to a farm house on top of a hill.
- Your weeping tile system flows pretty good during a rain.

As moisture from the sub-soils pass through the concrete it dissolves unreacted slats in the concrete (lime, calcium, etc.) and brings them to the surface as a solution. The water then evaporates and leaves the salts behind in the form of efflorescence.

Given that your home is built and it is impractical to install a membrane beneath the foundation sab, one is left with a surface treatment. There are lots of sodium silicate based, liquid, penetrating concrete sealers available that when applied seek out the slats in the concrete which together form into Calcium silicate hydrate which increases the density and strength of the concrete and make it impermeable to vapour and moisture migration. It also locks up the salts in this matrix, thus eliminating the efflorescence as well. this is not intended to be a waterproofing solution.

Crystalline waterproofing is a viable option for waterproofing the basement from the inside. this process uses a cement slurry with active ingredients that use moisture to carry those active ingredients into the capillaries of the concrete and forms a non-soluble crystalline structure that is integral to the concrete and renders the concrete waterproof.

You need to first treat the moisture migration problem otherwise you’re looking for trouble. That air-gap membrane you applied is not waterproof. It will allow moisture to get trapped under your flooring and over time will cause mold. You may wish to consider crystalline waterproofing.

All basements will leak, it’s just a matter of time. It is best to waterproof a basement before finishing so you don’t lose your investment into finishes, furniture, electronics, etc.

Sub-floors while warm and softer than concrete can and often do hide water infiltration problems into basements. Water can leak for long periods of time without the owner knowing due to the raised nature of the floor. This can lead to damage of wood sleepers and unhealthy mold growth. I recommend against them unless a basement has been waterproofed.

You also will have several foundation wall cracks all of which should be injected with a flexible resin prior to finishing the walls. These are most common basement leak problem and the least expensive to repair. There are many DIY kits available if you wish to do it yourself like this one: Wise Choice Construction Products - Specializing in Concrete repair and resurfacing materials and makers of the Crack Seal Do It Yourself Concrete Crack Repair Kit

The bottom line is that you shouldn’t finish your basement until the moisture problem is resolved, the cracks are repaired and you can be sure your weeping tile isn’t soon going to fail.

I don’t mean to scare you or be an alarmist, but I have literally seen tens of thousands of wet and leaking basements and the devastation that happens when they leak when finished. An ounce of prevention is worth a pound of cure!

For more reading on the subject of leaky basements, causes and prevention, go to my blog by clicking here: PermadryBlog

 

[CHDinCT]

Hello,
The last two pictures that you posted look really good. I'm glad that everything feels nice and solid. So, now what are you going to put on top of the subfloor.....hardwood flooring, tile, carpet ????? Looks like you'll have a nice floor whatever you choose !!!! Good luck !!!!

MFWD

Nothing for now. Just going as far as the subfloor at this point. I wouldn't put anything over it unless we decide to finish the basement. In that case maybe laminate or carpet squares. Not sure.

 

[CHDinCT]

Given that your home is built and it is impractical to install a membrane beneath the foundation sab, one is left with a surface treatment. There are lots of sodium silicate based, liquid, penetrating concrete sealers available that when applied seek out the slats in the concrete which together form into Calcium silicate hydrate which increases the density and strength of the concrete and make it impermeable to vapour and moisture migration. It also locks up the salts in this matrix, thus eliminating the efflorescence as well. this is not intended to be a waterproofing solution.

Crystalline waterproofing is a viable option for waterproofing the basement from the inside. this process uses a cement slurry with active ingredients that use moisture to carry those active ingredients into the capillaries of the concrete and forms a non-soluble crystalline structure that is integral to the concrete and renders the concrete waterproof.
PermadryBlog

Well, now you tell me, LOL. Never heard of Crystalline waterproofing but it sounds like the solution I was looking for. Too late now, but I'm not that worried. The dehumidification system will keep the relative humidity below where mold will grow and the Platon membrane should prevent any dampness that does come through the slab from getting to the subfloor. As to the weeping system, I may dig it out in the one back corner of the basement near my bilco doors that seems to be the dampest come Spring. All in all, at this point, I'm pretty comfortable with my approach. If I were starting again, or for my next house someday, I'll take a look at this waterproofing system. Thanks