Moisture control with rubble foundation

[stevenragatz]

We have a very old farm house in Maine that has a 24X48 basement with a rubble foundation. The ceiling is just about 6', so it's a bit short, and not the best space for any use. Half has a rough, unsealed, but intact cement slab. The other half is just dirt. We have four small windows, that can be utilized as vents. There are two, brick chimney arches.

The humidity down there averages about 85%.

The house inspectors recommended installing a vapor barrier, and am starting to look into that. This has led to some questions...

Does it do any good to put down a barrier (10mil plastic) over just the earth half if the boulder walls are left bare?
If I run the plastic up the boulder walls, the only place I see to attach it at the top would be the inside of the sill. Would that be desirable/adequate?
Is there any benefit to putting down plastic over the bare-earth half and not doing anything over the slab?

Thanks in advance.

Steve

 

[bud16415]

Welcome to the forum.



It looks like they dug down a little on the side they put the concrete down on and left a curb up to the dirt. I would think about doing the same thing on the other side if budget allows.



I am no expert but I’m guessing most of the moisture is coming from the dirt floor as that fieldstone walls look pretty good and pointed up good.

The plastic is not that expensive so I would put it down and try it out. Even just putting down a 10’ square you should see water droplets form on the bottom. Simple test.

 

[stevenragatz]

Thanks! Actually, the photo isn't clear, and the curb goes the other way. The dirt side is lower.

The concrete is pretty rough, and marginally level, with no drainage - standing water wants to pool in the middle. I've done some grade work around the perimeter of the house, and added plastic with crushed stone over it, beneath the drip-line, to encourage the rain to wick away from the foundation, but we've had little rain this year, so I've not yet had a viable test.

"Budget" right now is a funny word after being unemployed for seven months, so I'm hopeful that there would be some notable improvement with only plastic.

This evening, I put down a 6X24 piece to see if droplets appear, as per your suggestion. The moisture detector down there reads 88%, and it's supposed to rain tomorrow, so it might be a good indicator.

Steve

 

[bud16415]

I took a closer look at the photo and can see that looks like a form board sticking up. So that’s good when the time comes it looks like you can finish the floor. People were shorter back in the day and digging by hand and horse was hard work not to mention setting those stones. Quite often they used the dirt to build up on the outside so as to not have to dig as deep also and then when they would get to grade switch from field stone to cut stone or blocks or brick like yours.



Looks like the center beam was weak and they added a heck of a lot of lally columns down the center. Lets hope they did proper footings also looks like 3 of them were done at the time of the pour.

I think you will find moisture. If money is tight I have added 2x2 pavers over the plastic to give some sort of a floor to an area and used it for storage. If you just lay the plastic for now and tape the seams make sure to rake out the dirt nice and flat so if you do something latter you will be ready to go.

 

[stevenragatz]

Now that we're moving into winter, the overall humidity has dropped significantly, so it isn't the best time to monitor. However, I did put down some plastic over the dirt, but have not seen any indication of moisture. There's little reason NOT to put down the plastic, so I guess the next time I'm in the "big city", I'll buy some. The question then is whether or not it makes any sense to put the plastic over just the dirt, or do I need to find a way to run it up the stone walls?

Thanks in advance.

Steve

 

[bud16415]

I would just worry about the dirt floor for now and next spring see if it is improved.

 

[stevenragatz]

Checked on the test patch, and most definitely, there's water beads underneath. So, I've bought a roll of 10mil sheet and will put it down over the dirt floor. Thanks.

Steve

 

[stevenragatz]

Update: Current basement status is a humidity level that seems to match the outdoor level. We're into fall/winter now, so it's not a good indicator, but even if I can get it down to the air humidity it would be an improvement.

Thanks for the tips! Hopefully the plastic will help.

Steve

 

[bud16415]

Looks good post back in the spring and let us know how it's working.

That brick structure in the center with the arch looks interesting. What is it holding up?

 

[stevenragatz]

The arch is one of two arches below the lower level's fireplaces. The other one, not pictured, is larger, and older. The bricks on it are much softer and spalling, which is one of the big reasons I want to lower the humidity down there.

Steve

 

[bud16415]

The arch is one of two arches below the lower level's fireplaces. The other one, not pictured, is larger, and older. The bricks on it are much softer and spalling, which is one of the big reasons I want to lower the humidity down there.

Steve

Amazing the level of craftsmanship they had back then. I'm also impressed at how the brickwork ties into the stone work.