Hi folks,

A few years ago, when Hurricane Irene hit, the carpet in the finished portion of my basement got damp in multiple spots by a small amount of water that infiltrated the room. That carpet and pad was laid directly on the concrete floor by the previous owner. Fearing future mold, we had all the carpet removed.

I'm now preparing to re-carpet that room. I'm laying down DMX 1-step dimpled underlayment directly on the concrete and then laying a floating subfloor on top of that. The 5/16" height of the underlayment should be enough to keep the subfloor dry if water ever comes in again, but just in case, I'm going to use either Advantech 23/32" T&G OSB or GP DryPly Sturd-I-Floor 23/32" plywood. Both are water resistant.

My questions are:

1. Does anyone have any thoughts or opinions on Advantech or DryPly?
2. For a floating T&G subfloor, do I still need to leave a 1/8" expansion gap at the 4' ends?
3. Should I use a construction adhesive in the groove?
4. Lastly, for anyone who is familiar with water resistant plywood/OSB......Is only the factory edge impervious to water? When I cut a piece to fit in near a wall, is that cut end not protected?

Thanks to anyone who can help me!!!!!

 

I think that you are putting too much faith, in those materials. If the waters enters again, they won't save you, from removing it again. Consider rubberized flooring & forget about the carpet.

 

Hi Jeff,
I agree with Pulpo that you are optimistic with your approach. Unfortunately the reality is that dry basements are made from the outside in, an end result that can rarely be accomplished from the inside out. And believe me, I don't say that just to be a pain.

Water is only one of the moisture issues and you have it, even if it is rare, where will it dry to?

Moisture vapor is next and you, like 99% of all basements, have that as well. It can pass right through concrete and will seek to equalize the inside level with the outside. Install a vapor barrier and it will become as wet behind that barrier as the soil outside.

Capillary action will wick moisture from the footings below the house up through the entire foundation. If memory serves me it can lift several hundred feet through concrete.

The there is condensation, but that gets into the wall treatment.

And don't forget Radon mitigation, NY is in a high concentration area.

Bottom line is that basements are a hole in the ground designed to hold up a house and little more. For those building a new home who really want a dry basement, (in NY) the cost is extreme and the work must be done during construction.

Lipstick applied to a water/moisture problem in a basement rarely works.

Bud

 

Part of this depends on the topography of where you live. Ignoring catastrophic events, like Irene, how well do you drain? My parents, for instance live near a flood zone in NY, but they are at such an elevation that their basement will pretty much never get wet spots (except for a hurricane, of course.)

 

Has a hurricane hit there more than that one time that you know of? I guess like the others are saying, it would be a gamble to put similar materials back down.

I did like the idea that was posted about going back with rubber flooring of some kind. That would be ideal, and it is just the basement, so you don't have to have it like the upstairs.

 

Thank you folks for your input! I really appreciate it!! I'll try to answer the questions you asked me without writing a whole novel lol.

First, a little bit more information. Our basement is nearly half of our living space (900 sq ft main floor, 750 sq ft basement. There is an office, full bath, laundry room & den in the basement. The only room I plan to carpet is the den, which runs the full length of the front wall of the house. The office, bath & laundry room all run against the back wall.

I agree with Bud9051 that waterproofing from the outside is the proper way to do things. I did get 3 quotes ranging from $12k - $16k (there are a few areas that they can't get heavy equipment into and would have to dig by hand). Our house is now worth $110k less than we paid for it 9 years ago, and our outstanding mortgage balance is $60k more than the house is currently worth. Because if this, we just can't put that kind of money into it.

After the storm, we had a service rip up the damp carpet and they found no traces of mold. This carpet & padding had been directly on the concrete for the 7 years we lived there before the storm plus a few years with the old owners. There was slight moisture on one interior wall. All the outside walls (drywall) were dry. So to sum it up, in what could be called a 100 year storm, we got approx 1/16" of water in a few select spots of our basement. And that is with the sump pump not running for many hours due to power loss. A simple mop could have removed all the water.

I run a dehumidifier from spring to fall and keep the humidity level around 50%. In winter, the level is around 40%. I also do have a radon abatement system.

I noticed after the carpet was up that the water collected at two low points near the wall. I plan to cut 4x10 holes through the carpet, subfloor and underlayment at those spots and cover them with a floor grate. In the event of any extreme rainfalls, I'll be able to lift the grates and check for any water. If any is present, I can suck it out with my wet/dry vac and run my spare dehumidifier along with the primary to get rid of the moisture quickly. I'm also leaving a 1/4" gap between the underlayment and the walls to allow airflow under the floor.

I'm also going to have a few yards of soil trucked in to place around the foundation. Most areas up against the house are totally flat with no slope away from the foundation. A few months before the storm, we had all the large shrubs dug up from the front of the house (within 2 feet of the foundation). That disturbed a lot of hard packed soil, and my have contributed to the first time water infiltration in the den.

Michael....We live at a high elevation. The backyard does slope slightly towards the foundation. We do ocassionally get water in the laundry room and office (which is why we are not carpeting the office), but again, only in super severe rains, and little enough that some newspapers or a mop can get rid of it all.

I realize this isn't the ideal way of doing things, but from the hundreds of hours I've spent researching options, I think this my be my best choice if I'm dead set on carpet. I'm also aware that I'll have a heck of a transition from the carpet to the non-carpeted areas.

Again, I appreciate everyones advice and warnings. As far as my original 4 questions, any answers?

Thanks again!!

 

Before you add the top soil, look for hairline cracks, in the foundation & check the gutters & downspouts. If there are cracks, the foundation needs to be exposed & sealed.

 

Pulpo.....That's a really good idea. There actually is a small crack in the foundation along the front wall that the previous owner seems to have patched up with some type of sealant. I will take a closer look at it and dig down a bit below the current soil level to confirm it really is sealed completely. Hopefully that crack doesn't extend too far down!

When I had the sump pump put in, I had the guy also run my downspouts into underground pipes to run the water away from the house. The previous owner had simple splash blocks and the water was all draining within about 2 feet of the foundation.

Thanks for the reply!

 

Chances are the crack goes all the way down to the footing & chances are that it was never sealed that deeply. The idea is to stop the water from entering, so a sump pump isn't needed. If you are on the south shore of Long Island, you need to know how high the water table is, in your area. I had a couple of jobs there, to dig, to try to find the water table. Of course, I hoped that I would hit water in a few feet but I had no such luck. Both of them were dry as a bone after 9'. I have also done a lot of foundation water proofing, mostly in Port Jefferson. I can explain the process, if you need, to know.

 

Hi Pulpo,
I'm up in a real hilly area of Putnam County. Nothing like the flat lands of Long Island. Even though I am up on a hill, people in the area say we have a high water table.
I'm hoping that crack doesn't extend too far down, and hopefully the sealant they used is still in place, but as the ground is still frozen solid, I won't know for a while. I'm thinking that that crack may be sealed ok, because up until Hurricane Irene, we never had any water in the front part of the basement where the crack is located.
When I see on the news about people who end up with 2, 3 or 4 feet of water or more in their basements after major rainfall events, I almost feel lucky that at most, we end up with a few 1/16" puddles. Of course, total dryness would be ideal, but with the work and cost involved in proper foundation waterproofing, and a house where we are so upside down on the mortgage, it just isn't worth it for us to sink extra money in.
Thanks so much for your input!!

 

I would did a test hole. See if & where you hit water. The cost might not be as bad as you think, to seal the foundation. If you hire day workers, it can be under $2,000.

 

Actually, it's probably a bit more difficult than you'd think to dig all around our house and seal the foundation. I've got a 550 gallon underground oil tank buried right next to the foundation on the south side of the house. I've got brand new front steps on the east side, and I've got a pad and central A/C condenser unit right against the north side of the house. Plus, pipes leading out to the septic tank on the north side as well. Not an easy job.

 

I didn't expect you to dig "all around the house". Just dig in the sections where the water enters the cellar.

 

Unfortunately, when we had the water infiltration, the carpet was damp in spots against all 3 walls in that room (the north, south & east walls), and we also had water in the office which is agains the west wall. So basically, it's all 4 sides of the house. Plus, since by the time the carpet was pulled up, the water had stopped coming in, I can't even pinpoint exactly where on each wall it came in from. In addition, the walls themselves are finished (drywall).
In this case, to do it properly, we'd have to seal all the way around the house, right?

 

In that case, you have to wait until you get some heavy rain or take my original suggestion which was the rubberized flooring. The water won't damage that type of floor. Then it won't matter when you seal the foundation. Either way, you are buying time.

 

When you say "rubberized flooring", are you talking about those squares that interlock together like you may see on the floor of a gym? Home Depot also sells something called Allure flooring which is supposed to be moisture proof. We thought about doing those originally but kept going back to carpet since we want to make it a warm, cozy space where you can comfortably walk barefoot and kids can play on the floor.
Even if any water infiltration would never be able to contact the plywood subfloor, padding or carpet due to the raised dimple membrane, would you still definitely not put carpet down there?

 

Rubberized flooring doesn't have to be squares although that is a choice. It also comes on a roll. The children can certainly play on it. There is less chance that they will trash it, too. I wouldn't want young children playing, on new carpet. The chemicals, in a new carpet, are not healthy, for the children or pets.

 

I really hate the idea of hiding a problem rather than fixing it...

If this thread was about a subfloor because your feet got cold, that'd be okay. But using it to avoid fixing another problem is a bad idea.

Also, if you go with a normal underpad and carpet, you'll be able to replace it 3 or 4 times for the cost of what you're doing, which will STILL need to be replaced if you get water.
But, it's your money, spend it how you like.



*** to correct an earlier post: properly sealing any leaks will not negate the need for a sump pump. Having that hole in the basement floor, plus the pump, prevents massive amounts of pressure from building up under the house, which could cause the floor to crack. If it was completely watertight, it'd be like a boat, except a boat is designed to float and your house is not.

 

m_bisson.......Thanks for your reply. I realize that what I'm doing isn't the optimal solution, but as you can see in reply #6, I had 3 price quotes for fixing the basement the "correct" way, ranging from $12k - $16k. I can't sink that kind of cash into a house that has lost so much value that even if I wanted to sell it in 5 or 10 years, I couldn't because the mortgage is so far underwater due to falling home values.

The price for what I want to do is $240 for 3 rolls of DMX underlayment and $347 if I go for 12 sheets of the more expensive water resistant Advantech T&G subfloor. That's $587 to keep the carpet and padding 1.03" above the concrete. The deepest water I've ever had was about 1/16", and that was during a 100 year storm with the soil around my foundation either totally flat or sloping towards my house (back yard). I'm going to be trucking in soil to improve the grading.

As a side note........We've had a massive amount of snow this year, which has all melted away recently, plus a super heavy rainstorm 2 days ago. My sump pump has been cycling on approx once every 45 minutes, and my basement is bone dry.