OK, so a number of you have helped me out on the recent basement flood: https://www.askmehelpdesk.com/plumbi...-242374-3.html Many thanks! My solutions to avoid the rain flooding are to re-grade the outside and sink a few drywells connected to downspouts.

Meanwhile, the basement has bloomed some mold, but we wanted to finish the basement. I plan to pull back the drywall to fix it. (The basement is currently partially finished.)

Since I want to re-finish the wall properly, HOW DO I SEAL MY BASEMENT WALLS SO THAT THEY NEVER GET MOLD DAMAGE AGAIN?

I have some ideas, including: Drylok-ing the cinder block walls; vapor barrier-ing my new framing; stiff foam insulation; fiberglass insulation; 1/2" space below the new drywall for air circulation. (By the way, we are *not* concerned about temperature or heat loss down there.)

Does anyone have a reasonable approach for re-finishing the basement walls so that moisture condensing through the cinder block does not cause mold?

Thanks,
Justin

Based on your previous post I think you would be well advised to bite the bullet and put in drainage pipe around the perimeter of your basement before doing any finishing work. DryLock if fine for repelling dampness. It will not seal out any water. Forget the moisture barrier and the 1/2 in gap. A moisture barrier keeps warm and cool air masses from mixing which creates condensation. It does not seal out moisture. A moisture barrier such as plastic fixed to the cinder block wall would only keep the moisture confined to the block and make things worse. A 1/2" gap at the bottom of the drywall would not allow for air circulation because the wall cavity is filled with insulation. If the cavity were not filled you would still have to have a gap at the top of the wall, below the top plate, to allow for circulation. You would also have to have a temperature difference to cause air circulation.

Think about it like this. Rain fell. The water soaked into the ground. This rain may have fell on you roof and ran into your yard, or it may have fell in your yard, or your neighbors yard, or even in the mountains far, far away. It is now traveling under ground on its way to the sea. Your house is in its path. If it can't find a way around your house the water will back up and the pressure will increase until it finds a way in. That way will be thru any crack or voids in the block or the mortar. It finds cracks and voids in the outer surface and then flows down the holes or cavities of the block to the footer. There it sits until it builds up enough pressure to push it through the inner wall. It is very difficult to make something water proof. It is much easier to divert the water. That is give it a path with less resistance. This is where you give that path.

You can put in the drain age pipe yourself if you back is strong enough or you can pay someone else if you wallet is strong enough.

Let's say your back is strong enough. Rent an electric concrete or pavement breaker. Cut out 24" of basement floor all around the basement walls. Dig down to below the footer. Punch a hole in the cinder blocks. One hole for each cavity in each block. In a convenient location, usually a corner, dig a hole and put in a sump pump crock. Drape you trench with nylon fabric, put in perforated pipe. Pipe drains to sump crock. Fill trench up to bottom of basement floor with gravel. Put short lengths of 1/2" PVC pipe in each cinder block hole. Fold fabric over gravel. Fill trench with concrete and refinish basement floor.

This way it doesn't have to be expensive but it's a lot of hard, loud, dusty work. You will have to haul out all the concrete you burst up, and the dirt you dig out. You will have to haul in the gravel. Most likely you will have to mix the concrete yourself. That mean you will have to haul it in dry and mix it in the basement or mix in outside and haul it in wet which makes twice as heavy. You can get it ready mixed but you better have a lot of people to haul it in. The truck will only sit so long. You can get a pumper but it will be expensive. If you mix it yourself and get the bagged premix, get a couple of bags of portland cement. Add a shovel of portland to each 80 lb bag to increase the strength of the premix.

You can pay a water proofing company. Someone I know just paid 18K to have it done, plus 4K to me to fix the walls after it was done. They finished the basement first and all the studs and drywall had to be cut out about a foot up.

You said that you were not concerned about heat and A/C. If not, why insulate? Heat and A/C will go a long way toward removing moisture.

Be smart. Be relatively certain you have solved the moisture problem before even thinking about finishing the basement. Pay me now or pay me later.

I can't give Harold a greenie until I spread some around but I totally agree with him. I am afraid you aren't ready to drywall yet. Your moisture prevention efforts need to be tested by mother nature, I think you will still have a moisture problem unless you install a full foundation drain system and sump pump ( curtain drain). It also sounds like you need to increase your ventilation and air flow. Does the basement have sufficient air ducts, turn your thermostat fan setting to ON rather than AUTO.

OK, so apologies for not replying sooner, but I wanted a little more time to see how my efforts have played out.

So far, we have done a few things:
1) re-graded the ground around the basement -- it now drains away from the house
2) installed a French drain to collect and divert the rainwater runoff
3) installed a drywell that is attached to downspouts to further dry out the ground around the house.

We have had 2 very strong storms (2+ inches rain, plus wind) this week and I have had no water in the basement.

I think maybe my question was not clear. I know I wasn't ready to drywall. I'm not planning to for a while. (Believe me, I don't want to do ANY work that I will have to UNDO.)

BUT, I want to minimize the minuscule amount of moisture that might wick through an old concrete wall. I'm thinking I'll begin with Drylok. Basically, I'm trying to be certain to avoid mold damage BEFORE I drywall.

Thoughts on the process?

Ballenger: there is no ventilation. Do I need that? Recommendations?

Harold: re: insulation
-- all I'm saying is that the basement keeps pretty warm in the winter and pretty cool in the summer, so no need to go beyond the status quo.

That good news but give it at least a year before finishing basement.

You can pay a water proofing company. Someone I know just paid 18K to have it done, plus 4K to me to fix the walls after it was done. They finished the basement first and all the studs and drywall had to be cut out about a foot up.


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Just wondering what did you do to fix the walls. Reason why I'm asking is because I just had a water proofing company install the french drain system. And know 1 weel later I'm have a lot of crack show up on my basement wall's. Is that common or did the screw something up.

Do you mean cracks in the basement walls or cracks in the drywall?

I put down a new sole plate, scabbed on short lengths of 2 x 4 to studs, replaced dry wall, finished drywall, painted did some patching to floor tile. The 4K actually included some other work but I was making the point to make sure basement is dry before finishing off to a living area.