Sealing concrete gaps

[JackAndy]

Can you recommend a product to seal the gaps between the concrete blocks in my well room and basement foundation?

The gap is narrow at the bottom and wider at the top. The blocks on the left is the foundation of the house and the blocks on the right is the well room. This pictures is from inside the well room.

The gap is about a half inch at the top. Some dirt was actually coming out of it so I think mud had flowed through it at some point.

This is the layout of the basement. The room off the foundation is the well room.

 

[ethan.jordon.3]

NP1 sealant. Comes in caulking tubes. Works great for that

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[JackAndy]

The Amazon reviews for that stuff (Sonneborn NP1 sealant) make it sound really great. Xylene based so it remains flexible and soft and super sticky. Home Depot doesn't have it at all though and Lowes only has it online so I might have to buy it from Amazon. Thats alright I suppose. I'll just pump as much of that into the crack as possible.

 

[ard]

What is it you are trying to achieve?

If that is all below grade, and has hydrostatic pressure behind it during wet seasons, anything you put in will ultimately fail....

 

[cmc76]

before just pumping as much as possible, back up a step.
do you have water intrusion? air getting by?
caulk is not meant to just pump in as much as you can. get backer rod. ( foam that comes in diameter in rolls ) that gets pushed in first. depth will depend on your gap. then you apply your sealant.
as ARD noted, if there is pressure caulk does not act as an expansion joint. you will need a different solution.

 

[ethan.jordon.3]

before just pumping as much as possible, back up a step.
do you have water intrusion? air getting by?
caulk is not meant to just pump in as much as you can. get backer rod. ( foam that comes in diameter in rolls ) that gets pushed in first. depth will depend on your gap. then you apply your sealant.
as ARD noted, if there is pressure caulk does not act as an expansion joint. you will need a different solution.

Exactly. I forgot to mention that. We always put a backer pad in it before we seal up cracks in dike walls and floors at work. Thanks for throwing that tidbit out.

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[JackAndy]

What is it you are trying to achieve?

I'm trying to turn the well room into a storage room. I'd like to get the humidity down to 50% so the stored items don't rust. Its currently at 65-67% in the whole basement including the well room. The well room smells a little damp. There were old wooden shelves from like the 60's in there. When I tore those out, there was some dirt on the shelves nearest the side where the gap is. When I got everything out, I noticed the gap and I figured that the dirt must've come in through that gap.

If that is all below grade, and has hydrostatic pressure behind it during wet seasons, anything you put in will ultimately fail....

Not all but most of it is below ground if thats what you mean. The first two blocks (where the gap is widest) are above ground. The well room actually used to be the front stoop according to the realtor. That doesn't make sense to me because the ceiling to it is wood. Anyway, above the well room is an entry way and closet now. There's a front stoop and steps in front of that.

I just bought the house and the previous owners redid the basement and landscaping. They added grading along the entire house. It slopes away from the house. Then they put black plastic on that and then little rocks on top of the black plastic.

Kind of unrelated but there was a wasps nest or something that I found at the same time as the gaps. I'm guessing they probably got in through that gap. I'm including the picture because it actually shows the ceiling. For whatever reason they put insulation up there which doesn't make sense to me because the well room is inside the house and above it is still inside the house.

 

[JackAndy]

before just pumping as much as possible, back up a step.
do you have water intrusion? air getting by?
caulk is not meant to just pump in as much as you can. get backer rod. ( foam that comes in diameter in rolls ) that gets pushed in first. depth will depend on your gap. then you apply your sealant.
as ARD noted, if there is pressure caulk does not act as an expansion joint. you will need a different solution.

I'm not sure if there is water intrusion but the dirt makes me think that there was at some time. That might've been 50 years ago, I have no idea. I don't think there is air getting through.

Ok I can get the backer rod. Its actually a fairly small gap and is just a crack at the bottom but I can put a small piece of backer rod in at the top as far down as it'll go.

 

[kbs2244]

Is the well room under the front porch?
If so the insulation was to keep the room warm.
Broom you gap clean, put in the backer roll, and the caulk.

Do you have a noise problem with the pump?
If so a heavy, solid door would help,
But it would not help he humidly without a dehumidifier for that room only.
If noise is not a problem then a door with vents will let a whole basement dehumidifier work.

 

[JackAndy]

Is the well room under the front porch?
If so the insulation was to keep the room warm.
Broom you gap clean, put in the backer roll, and the caulk.

Do you have a noise problem with the pump?
If so a heavy, solid door would help,
But it would not help he humidly without a dehumidifier for that room only.
If noise is not a problem then a door with vents will let a whole basement dehumidifier work.

Its not under the porch anymore. Its under the entryway.

The house has city connected water now and the well has been filled in with concrete it looks like. The floor is covered with vinyl but it looks damp under the vinyl.

There's an HVAC hose in the ceiling of this room that feeds a vent for the entry way above it. I considered just putting a splitter on there somehow to let some of that air into the well room.

 

[ard]

Put an airtight door on it...and convert it into a wine cellar. With the humidity I bet it stays nice and cool..... many many years ago in the old farmhouse where I grew up my dad concreted the basement- except on corner for his wine cellar. Dirt floor, dry stack stone walls. Tough on labels, fine for the wine.

 

[GS-Louie]

The only way to correct a crack in a basement wall is to fix it from the outside. Since the walls are not interlocked they will move differently and caulk will not stop that. Find a crack repair business and have them look at it. Look for one that specifically deals with cracks. You will be better off in the long run.

Lou

 

[Tejay]

I suspect a lot of the exterior work- drainage, gutters , etc. was an attempt to stop the leakage. I'm thinking you may need to excavate and parge/ tar the block and then a membrane over. Big O / drain tile at the foundation wouldn't hurt either. Yikes it's a big job!!
Get a foundation sealant contractor to give you some recommendations and pricing.

 

[BombShelter]

Well rooms always seem to be damp and wet and it's extremely difficult to dry them out without exterior waterproofing. The roof was probably gutterless at one time and the slopes of the roof directed water near the well room. Larger storms might also create overflow at the 90 degree turn in the gutters again landing in the same spot. At minimum dig down a couple feet where you see the cracks and expose them, clean them up and fill with hydraulic cement. Concrete and asphalt products become brittle over time so you need to put something over that repair for flexibility if hairline cracks redevelop.

I think the wood ceiling you see is left-over form from the concrete step pour and the insulation is up there because the room gets cold but the landing above it gets warm causing lots of condensation. These rooms are not usually good for storage of anything that might be affected by condensation.

 

[JackAndy]

Thanks guys. I really appreciate your feed back.

 

[JackAndy]

I cleaned the walls with a steel wire brush and painted them with Drylok. I actually ran out half way through the second coat and found a different brand of waterproof concrete and masonry paint just sitting in the utility room so I started with that one too. Its slightly glossier and can be seen on the top half.

The 1/4" backer rod would barely fit in the crack. I managed to squeeze it into about the first 3 blocks from the top. Only one of those is even below ground. The crack is too narrow after that. So that will have to wait on the NP1. I haven't even ordered it yet actually, kind of busy.

The paint really brightens up the room at least. I think the floor under the vinyl is also damp. That might need to get coated with the same paint actually if I want to eliminate the smell/humidity. Then I'd just roll the vinyl right back out on top of the painted floor.

 

[JackAndy]

I got the NP1 sealant from Amazon but it was all dried out and wouldn't dispense. Does anyone have recommendations for a product that I can get locally that won't be all dried out? Lowes and Home Depot don't carry NP1.

 

[JackAndy]

The replacement came and I was able to get that to dispense and the cracks are all sealed up.

 

[rnscustom]

Most masonary supply places have it