Official Luthiers Forum!

We are looking to move to a new home. Among the many criteria for our next house is having space for a workshop in the basement. My current shop is in the basement with framed walls and drywall. The floor is concrete that I painted with a few coats of oil based floor paint (hoping to slow some of the moisture). It is difficult to keep the RH down during the rainy times when the ground is saturated.

Not knowing what the next house will look like, I'd like to get a handle on the different scenarios. We may end up with a house that already has a finished basement in which case my options for keeping moisture out are pretty limited. We may end up with a completely unfinished basement which gives me options but then the cost of those options (both financially and in the time it will take me to get done so I can have a shop again) has to be factored in to the choice of house.

What are the best and or fastest and or most cost effective solution for keeping moisture from migrating through a concrete foundation? Ideally you will tell me there is an inexpensive product I can paint onto the concrete and then put up walls or go without walls all together.

Thoughts?

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

I only have one data point - which is my own shop, so....

I have had very little issue keeping my basement shop under RH control and I believe it is primarily due to using dricore panels from Home Depot as a subfloor in both of my “shop” spaces. The spaces stay very close to the desired RH on their own and the dehumidifiers don’t have to work super hard even in August in the swamp of Ohio.

I’ve heard the difficulties discussed here, but I just haven’t seen it.

Again, a single datapoint.

One other aspect that could contribute is I have a sealed sump pit.

Edited to add - not cheap (sorry )

Brad


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Lord knows I am no expert, but here are some things I know.

The most effective way to keep water from seeping through the walls and floor of a basement is to give the water somewhere less burdensome to go. That would mean either a well designed and functioning drain system on the outside of the basement wall (the dirt side) or an interior drain system installed in the floor just inside the basement walls. A sump pump system falls in this category, too. If the water can easily go somewhere other than creep through the walls and floor, it will.

The other side of that coin is that, if you are not giving the water somewhere easier to go, then every other solution is going to be prone to problems at some point. Yes, you can paint the walls. But then the concrete on the dirt side gets wet, and hydrostatic pressure builds up, and eventually, the water is going to find a way into the basement. It is like pushing an empty bucket down into a swimming pool. If there is a small hole in the bucket, the water pressure will push hard against that small hole, and the water will gush into the bucket via the hole. Your basement is the bucket, if you are not giving the water somewhere else to go.

The systems that promise dry finished basements tend to create a mold resistant path for the water that has found its way into the basement. Think of DriCore subflooring, or Delta-FL. It doesn't keep the water out; it gives it an easy path that is below the stuff you want to protect from water.

So, full basements are tough if they are not designed and built the right way. Walkout basements are a little easier, because at least the water is not trapped in a pit.

I wish I had better news.

Thanks for the responses, keep them coming.

To clarify, I am not having water come in per we. There is no water on the floor and the walls are never sweaty or damp. It just seems like the concrete is letting the moisture from the soil penetrate and raise the RH. Usually I don’t have much trouble with RH but we are having record flooding here in the St. Louis area and the ground is just wetter than usual in general. Hopefully, the new house will not have a leaky basement but I guess you can never really know for sure until you are there. What I want to do is figure out what reasonable steps I can take to make maintaining RH as easy as possible when building a new shop. Or, what I should avoid doing.

I suppose the question mostly applies if I find a house with an unfinished basement. Am I better off with painted concrete walls or stud walls, drywall and a vapor barrier of some sort, or something else? I am considering the vinyl floating floor because it is fairly cheap and seems like it would be a good vapor barrier; but, what do I know?

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Epoxy floor paint worked well in my garage.

You could look at the type of soil around a prospective new house. By sheer dumb luck, before I started building, we bought in an area with sandy soil that drains really well, so our full basement, where I store some of my wood stash, is dry all year around. Don't know how a situation like ours would play out in the humid midwest.

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formerly known around here as burbank
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http://www.patfosterguitars.com

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Have a look here Bryan. lots of information and research here.
essentially, if you have water issues, you need to take care of them first.
other than that, you shouldnt trap moisture but control it.
I have completed my basement in this manner and it has made a big difference.

gregor

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Wake up and smell the rosewood!

When I had the same 'opportunity' lo those years ago, I sealed the floor with clear concrete sealer and painted the walls with waterproofing paint intended to be spread on concrete basement walls. The white color of the paint helped make the shop brighter, too. I run a dehumidifier, and I can hold 35% RH.

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Peter Havriluk

My understanding is that concrete is pretty much transparent to water vapor. Painting the inside surfaces also doesn't work well because concrete has very little tensile strength, so that water pressure can simply push the paint off, no matter how strong the paint is. The bottom line is that to make things really dry you have to coat the outside of the foundation with some sort of vapor barrier, and that includes the floor. Obviously this is best addressed when the building is going up. Walls can be retrofitted, and with good drainage around the edges of the foundation the problem can be minimized.

I worked out of the worst case basement workshop to begin with. It was an older house, in clay type soil. The builder had dug the cellar hole out, throwing the dirt and rocks to the outside. They used the rocks to make the foundation and back filled with the dirt. The old mortar was crumbling, and the head room was only about 6'6". About the third time I stood up and broke a light bulb I decided to dig out the floor. The only problem was that the foundation only went about 3" below the floor level. I spent then next six months digging down in 2' sections and filling in new footings with concrete mixed in a wheelbarrow (poor luthier). Once that was done we poured a floor of waterproof concrete. In the end it was better, but the the R.H. seldom went below 55% in the summer, and the temperature would be around 80-85 degrees with the dehumidifier running constantly. Then the back yard filed up with water in a deluge, and it came in over the sills....

If it were a preexisting unfinished basement with no leaks, could you frame in the room with studs and drywall putting plastic on the inside of the stud walls? Leaving a small space between the concrete and the framing would allow water vapor to enter as it needs to but disperse around the sealed room. Could you put plastic down under whatever floor you added or do you need airspace?

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Epoxy works great. Unless it doesn't. When it doesn't it is a bear to remove to do something else. I had a situation where there was enough moisture coming through the concrete that the epoxy slowly lifted in bits and pieces. This was on a 6-month cured slab, prepped surface and applied per manufacture specs.