Sealing / Waterproofing access in CMU wall under porch

[DuckRyder]

So we are talking about a early 70's basement ranch, the basement is built with CMU/Concrete block, it has a Brick facia on the front. the front and one side of the basement are underground. the garage side and rear are above ground, this is typical in the area.

The interior of the basement is finished by nailing 1x3 to the CMU as furring strips and nailing typical 70's era luan paneling to it. (also typical construction)

The house is roughly rectangular with an entry way in the center of the front and a porch (also brick).

There is a 2x2 void in the concrete block that provides access to the underside of the entry way. this is allowing moisture in.

Yes the grading needs attention and will be taken care of (to direct water away from the home) also the years and years of much and leaves have already been removed.

I'm looking for ways to seal the 2x2 hole non-permanently to reduce the entry of moisture.

Ideas?

 

[Cujet]

Any chance for a pic? I'm not sure what you are trying to seal? Fill the hole with concrete?

 

[JTK]

I'm also having a hard time visualizing and not sure what CMU is or non-permanent sealing.

Assuming you don't plan on sealing the concrete block from the outside once you address any drainage issues, I've used a product called thoroseal on concrete block to hold moisture back. It worked well.

 

[JC1]

Are the cinder blocks already sealed on the outside?

So the 2*2 entry needs to stay open or can be temporarily blocked until access is needed? Is that a crawl space? As others have said, post a picture.

 

[DuckRyder]

CMU = Concrete Masonry Unit (AKA concrete block)

The hole.

It is under this:

Here is a shot of the backside of the Luan:

And the front:

Basically i'm looking to seal this in some way in which there could still be access if needed, thinking perhaps a "wall" built out of 6x6 and installed with spray foam...

That is what i mean by non-permeant. obviously I could just fill it with more block.

I'm also wondering if I should bother with a plastic vapor barrier as well under the porch.

 

[JC1]

Oh the hole is on the inside.

Is that tile on your porch? Appears that water is leaking/seeping in. Is the structure which looks like wood joists moist/wet?

I would probably make some sort or access door to panel to keep the moisture out of your basement. You could Frame the perimeter of that opening with 2*4 or 2*6 and then make a panel that would be pushed in. Use backer rod or some sort of gasket to seal it. The panel on the side of the basement would be larger than the opening to conseal the framing.

Don't bother with vapour barrier on those walls on the other side.

I'm guessing that structure has no vent holes to allow air flow and reduce moisture.

Can you drill two small holes 4-6 inch under the porch to allow airflow? I would Block the opening with metal screens to keep critters out.

 

[Warstud]

There is a 2x2 void in the concrete block that provides access to the underside of the entry way. this is allowing moisture in

You need to explain this better. Are you saying that the area under the front porch is making your basement more humid ?

 

[DuckRyder]

Oh the hole is on the inside.

Yes, correct

Is that tile on your porch? Appears that water is leaking/seeping in. Is the structure which looks like wood joists moist/wet?

Yes the porch is tile, over concrete, the "ceiling" of the crawl space is steel crossmembers with corrugated steel over which the concrete is poured at least thats what it looks like. This is also typical in the are from what ive seen the door framing was dry.

I would probably make some sort or access door to panel to keep the moisture out of your basement. You could Frame the perimeter of that opening with 2*4 or 2*6 and then make a panel that would be pushed in. Use backer rod or some sort of gasket to seal it. The panel on the side of the basement would be larger than the opening to conseal the framing.

Gotcha

Don't bother with vapour barrier on those walls on the other side.

Nice that will save me crawling in there with the shiny black spiders.

I'm guessing that structure has no vent holes to allow air flow and reduce moisture.

Can you drill two small holes 4-6 inch under the porch to allow airflow? I would Block the opening with metal screens to keep critters out.

I do not see any vent holes or ventilation, the area in this "crawl space" is completely outside the living area. it appears to be only brick.

 

[Boomer]

One word for you.... termites! I had the same type of structure in my previous home. Furring strips nailed to block and an entrance to the outside. Termites got in unseen and for years apparently ate away the furring strips and then moved on to the support beams and the wooden floor above which was covered from below with a dry wall ceiling. Big bucks!!!!!!!

 

[JC1]

Yes back in the 70s they never worried about mold and moisture. I would add two holes to get air flowing in that space. In guessing in the bottom of that space it's a dirt floor?

 

[Warstud]

Maybe cut a seperate piece of luan paneling to size of void to use as an access door and add a return duct vent to it.

 

[RhondaHonda]

I’d fix the grade outside and put a dehumidifier in the basement and call it a day. Maybe some plastic over that hole if you wanted.

 

[PimTac]

Styrofoam. Cut to size, glue to some scrap plywood. Outer entrance needs screening.

 

[DuckRyder]

Ok, thank you.

yes it’s a dirt floor. BTW the house is in TN since I know strategy might vary by climate.

I have decided to build a panel out of 2*6 pressure treated an pt plywood. I will put it in with spray foam.

when the grading is done I’ll consider putting some vents in the porch. The grading will involve removing some trees.

the house had a termite inspection (2 actually) and got a clean bill of health. We will be removing the paneling and replacing with drywall so will give opportunity to inspect further.