Foundation Flooding and Ductwork

 

PAM: I have a house that was built in 1972 and it’s built on slab. The entire center of the house is an atrium and it has a slate floor.

TOM: OK.

PAM: And under the atrium part, the – well all the ductwork is galvanized and …

TOM: Does it go through the slab; through the cement floor?

PAM: Yes. Yes, it is.

TOM: OK.

PAM: And in the atrium part – we have narrowed it down to the atrium – there are pretty large holes in the galvanized ductwork and when we have rain the rain seeps in and sometimes it’s almost to the level of the cement and we have to pump it out.

TOM: OK.

PAM: And I was wondering if there’s anything you can recommend to seal these galvanized ductwork areas.

TOM: Pam, unfortunately this is a fairly common problem that a lot of people complain about and there’s really not a lot that you can do but I’m going to give you two tips that could help.

PAM: OK.

TOM: First of all, we want to try to see if we can reduce the amount of water that’s finding it’s way up into those ducts and the solution here is the same advice that we would give you if you were calling about a flooded crawlspace or a flooded basement. If you get a lot of water that collects in those areas when the rain is heavy, you want to try to take the steps to get the water away from the foundation perimeter.

 

So, for example, the gutter system; you want to take a look at the gutter system that’s closest to this atrium area and make sure that they’re clean and free-flowing and the downspouts are extending way away from the foundation. Also you want to look at the grade, the angle of the soil, as it slopes away from the outside walls. Those two things will help manage a lot of the storm water and keep it away from the duct space.

PAM: OK.

TOM: Typically, what ends up happening here is people give up on the ducts and then put in some other type of heating system. You can use the ducts as chases to run PEX tubing. For example, if you wanted to, say, take this portion of the house and convert it to a hot water system or you could, you know, use some other system or run ducts above it and try to push the heat down which is, frankly, challenging to do but sometimes when you have these heating systems in the slab it’s your only option. But I hope that gives you at least some place to start with it. It’s not uncommon and unfortunately it ends up with them rotting out and filling up with water.

PAM: Should we fill those ducts with cement?

TOM: Well, if you can solve the heating problem then, yes, you would seal them off.

PAM: Alright, that sounds good.