Hi All,
This is my first posting. I have what I think is a rather unusal problem. The concrete block walls of my basement extend out under the front step of my main entrance. The entrance is pored concrete and the concrete is exposed to the weather on top and the open basement underneath. My problem is that nothing I have tried will stop moisture coming through the step and into the basement. The problem is exaggerated by the large temperature changes up here in Ottawa Canada…. when it snows the snow melts and the moisure soaks in. I have tried concrete sealer but it doesn’t seem to work. I have tried insulating and tightly sealing a vapour barrier on the inside but before to long (a couple of months or so) there is a cloud of moisture on the inside of the plastic. Has anyone experienced this problem and do they have any suggestions.
Thanks
Replies
Welcome to Breaktime.
Concrete is permeable. Heck, anything is. Even roofing membranes have perm ratings in their specs but concrete is especially so.
IMO, this should have been formed with a drain plane and membrane under the crete stoop and the only 99%sure method to fix it is to remove it and rebuild.
Assuming that this is not a welcome idea, here are some others;
Build a roof out over the entry, then the door to door people don't have to stand in the rain while you decide whether or not to answer the door. It should also keep 75% of the rain off of the crete.
Paint it with an epoxy paint after cleqning the surface well. There are also urethene paints that are supposed to do pretty good at waterproofing.
There are cementious flexible roof coatings that look somewhat like cement too but I never used any to recommend.
Another stab at this might be a sprayed on urethene foam insulation from the inside. If your problem is condensation more than leaking, that will solve it.
Just some thoughts to kick around....
Excellence is its own reward!
"The first rule is to keep an untroubled spirit.
The second is to look things in the face and know them for what they are."
--Marcus Aurelius
If you've properly installed the sealer, then more than likely the problem has nothing to do with water leaking through the concrete but moisture condensating on the ceiling of the cold slab that's exposed to the cold winter temperatures outside.
If the moist air leaks past your plastic and into the airspace between the plastic and cold slab, it will condensate on the inside between the layers and give you the impression that it's leaking from above.
Clean it all out and this summer when it's all dry, have it spray foamed on the underside and your problems should go away for good.
Gabe
Thanks Gabe,
I was wondering about the foam insulation and strongly suspected the problem was condensation. The pad was installed as the building was going up and so is partly built into the surrounding structure ( the brick fascia was built on top of it at that point.) The roof of the house has large overhangs and covers the whole pad as long as the rain/snow falls straight down....not common in these parts! The house itself is 22 years old and someone had suggested that I dig up the foundation to install drainage tile. That is something I am comtemplating doing since I am pretty sure the drainage tile is not working....the original contractor learned his trade on this house if you know what I mean. The back fill is all soil and clay....a little gravel around the drainage pipe itself (don't ask how I know that!) ...but I don't think it wil make any difference with the porch step. Someone else suggested I use the space for a cold cellar and would agree except the builder (or subsequent owner) installed the sump hole there as well as the water softener and the well water entry point and pressure tank. A little crowded for a cold cellar...and not at all easily closed off.
Another question along the same lines that I was going to ask is why do I have effervesence on the walls (concrete block) and coming out of the floor just inside the room just in front off the insulated stud walls. I have been told that the reason this happens is that an excess amount of moisture is on the outside of the foundation and is being drawn into the warm dry basement. The suggestion was to install drainage tile...or fix the tile that is there. Do you agree with this suggestion? The effervesence (looks like cotton candy or mould) is only found along one wall...the same one as the front porch. On thing that I should have mentioned...there's always something....the foundation on the porch side is almost fully submerged below ground level. I had a landscaper come in and grade the property away from the house and even rerouted my sump discharge to the back of the property (since the front was higher). That did have a desirable affect since the sump pump runs much less now...but the effervesence is still there.
All current and future comments are welcome and very much appreciated.
Thanks
With all that stuff in there, you have several point sources for moisture to evaporate and re-condense on the underside of the slab. Insulation is no doubt your solution. It can be expensive to spray such a small space but if the bottom of the slab is a fairly clean smooth finish, you could easily glue in some extruded foam. Do the ceiling first and then the walls so the wall pieces hold the ceiling up. Use adhesive made for foam (PL300, I think) or spray foam filler works too. Enerfoam is one name.
Efflorescense is certainly from moisture in the crete but it could be getting there froim condensation on the inside too. Since you have clay soils and describe only a little bit of gravel, you have most likely got water held agaist the outside of the wall and a possible failur of the drains from no filter fabric and little gravel.
I would try the foam first, now, and then re-dig the drainage in spring or summer, if is doesn't work.
Good luck!.
Excellence is its own reward!
"The first rule is to keep an untroubled spirit.
The second is to look things in the face and know them for what they are."
--Marcus Aurelius
Hi Marcus,
Your suggestion sounds good although the underside of the concrete pad is anything but smooth...I can even see some of the 1" rebars as the builder clearly lay them in the bottom of the form before pouring. My question back to you is how will I know whether or not the fix worked if I cover the walls and underside of the pad? My fear is that the water will be held within the block walls and concrete pad if in fact the souce is not condensation. I would expect that the pad would soon develop cracks from the freezing temperatures if the water had no way out.....although if the water proofing works there shouldn't be any water in the first place.....the same wouldn't be true for the block walls though. I'm sure you can see my dilema. I had come to the conclusion that I would have to do the digging and drainage tile repairs first...see if the wall dampness and effervecene stopped and then reinstall the stud wall, insulation and vapour barrier ( I have had to remove all that in the area surrounding the sump and pump - under the concrete pad because of the moisture and subsequent mould that had developed) I feel like I am in a catch 22 in that I don't really want to dig up my property if I don't have to but I don't understand how I can be sure an interior repair has worked because the interior repair will cover the problem. I am sure that if the problem is still there I will see the result at some point down the road but at that point I will probably have an unhealthy amount of mould growing behind the foam..... Am I being overly paranoid?
Thanks
Are you or can you run a dehumidifier in that corner of the basement to dry it up?
Can you check the humidity level in your basement?
Did you try placing a 12" x 12" poly on your walls, floor and concrete ceiling with duct tape all around, to see if water beads form between the poly and the concrete?
Gabe
Hi Gabe,
I was using a dehumidifier and must have had it up to high as the effervescence seemed to become much more pronounced. The walls are not dripping wet right now if that was implied by my earlier remarks.....they are damp but not wet....there is the smell of dampness as well. I will follow-up on your suggestion of the plastic taped to the walls and I will see about the humidity level...I assume I should lower the level before I try the tape and plastic trick? I cannot apply the plastic to the concrete pad because it is much to coarse for the tape to bond.
Thanks again for the suggestions.
You can still do the poly thing on the underside of the deck by using a large bead of accoustic caulking first and then cover with the poly followed by the tape.
Yes the surface has to be dry first.
Gabe
Hi Gabe,
I am hoping you are still reading these postings and or someone else can provide some feedback. I tried the plastic trick you described and had no moisture show up between the wall and plastic throughout the winter. But come spring/early summer the moisture was there. None obvious on the wall itself because the wall is fully exposed to the basement air.
Right or wrong I have decided to excavate, replace the drainage tile, reseal the wall and insulate at the same time. I am having trouble finding information on the best method of sealing the wall against moisture and insulating at the same time. What I had thought of doing was to coat the concrete block wall with the usual black tar stuff and then apply some kind of styrofoam insulation followed by dimple sheet (made by Delta-MS or System Platon according to FHB foundations book). I was thinking this would be the best approach because it gets the insulation tight against the wall and the dimple sheet will help protect the insulation - especially where it comes slightly above ground level. But, I have also read that one of the benefits of using the dimple sheet is that it helps to drain off any moisure that comes through from the house to the outside of the wall...with insulation in the way that would not happen. I do wonder why moisture would be coming from inside if a moisture barrier was installed inside but I just don't know.
Does anyone have advice on how to deal with this situation? I would like to insulate well enough that interior insulation is not required. This means I must bring the insulation to at least the top of the foundation wall, which in some areas will mean it will be above grade. I Really appreciate any comments on this.
Thanks
Richard
But, I have also read that one of the benefits of using the dimple sheet is that it helps to drain off any moisure that comes through from the house to the outside of the wall...with insulation in the way that would not happen. I do wonder why moisture would be coming from inside if a moisture barrier was installed inside but I just don't know.
Skip that paragraph altogether and do the rest and all will be fine.
Upgrading your drainage is a big step in itself and adding the asphalt coating, rigid insulation and dimpled plastic will work well to give you a very comfortable basement for years to come.
Good luck,
Gabe
Hi All,
Just thought I would update this string based on what I have learned. Thanks to comments from Gabe I followed up with a search for the plastic dimple sheet for basement wall protection and styrofoam insulation. I received quite a few conflicting suggestions on the order in which these products would be installed against the foundation walls. Finally I was asked by one supplier if I had considered Perimate. This is a styrofoam product that has grooves cut in one side. To make a long story short it allowed me to buy one product instead of two. The cuts go out toward the backfill and all the styrofoam must be sealed together. I have used constuction adhesive and so far it has gone well. The big difference seems to be that with this product the water is directed to flow on the outside of the styrofoam away from the concrete wall where as the dimple product has the dimples against the wall and is designed to allow any water that enters to flow against the concrete wall down to the drainage tile. Not sure that one is all that much better than the other but I like the idea of insulating the wall (R12 with 2.5" product) and keeping water away from the wall all in one product.
If anyone has any questions on this I would be happy to share my experiences.
Cheers
Richard
Seems like you have a rural installation with a bit of a drainage problem......which part of the new city are you in so that I can get a handle on specific conditions. I know just about every part of the city and outlying areas.
By what your describing, I'm guessing that your lot's high point is at the front of your house at the street and your lot slopes back with your house interupting the flow.
If you want to discuss specifics, you can email me directly and I will try to help you out.
Gabe
Poor engineering. If basements extend beyond the footprint of the home, then the "ceiling" of the basement, e.g., the steps and the underlayment must be treated as a roof covering. I only have two ideas, to cover the front step with a large porch, or rip the steps out and properly waterproof the area.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1927
Actually it's good engineering.
This is very common in eastern ontario and most northern climates to create a cold room in the basement by having the front porch or landing over the common basement foundation.
Gabe
Id personally work to get the water away from the foundation. Not only would you help the moisture but eventually you can help thwart any uneven settling of your foundation.
Dig up and install drains below your frostline and get that water away from your house. Down the road when your foundation settles more at the wet areas and you see cracks, youll really seen and influx of water through your foundation.