Green Remodel Forum

The other day I removed the register on the floor to clean. I noticed the air duct connecting to the floor has gaps around it. I could feel the cold air coming in. What would work well to cover the gaps?

I like mastic. It's gray color. It looks like glue. Apply and cover all the gaps. You can get this material from a home improvement center.

While you at fixing the gaps between the ducts and the floor, You may want to check the connection of the air ducts. They are often loosened or separated, statistic have shown. By fixing that, there will be more warm air in the winter and cool air in the summer going into your home. And you don't want to heat or cool your attic/crawlspace.

It would be a good idea the applied mastic is as thick as a dime to cover the leaky area. In order for the air to flow smoothly in the room, avoid to place furniture on the vents.

Besides, you don't want that dirty air from the attic or crawlspace sucked into your home through the leaky ducts.

I think sealant clay is good is that purpose. You can also use clams to cover the gaps. Do you have photos of the gaps? That would help us to give much helpful advices.

Sealant clay is good for covering the gaps in the floor and prevent air coming in.

To Prevent heat in the winter and cool air in the summer from escaping, seal the cracks and holes with foam. Check the ducts and connections to see if they are loose or disconnected. Seal ducts with mastic with the thickness of a dime. If you are not the type of people like working in the attic/crawlspace, hire a building performance contractor do it for you. Make sure he is experienced, or certified by BPI (Building Performance Institute).

There are two main reasons for sealing ductwork in a home. First, and most obviously, no one wants the nice warm air moving through the ducts (which they just paid to heat) to escape before it reaches its destination and heats the different rooms in the home. Sealing the leaks maintains pressure in the system and gets all that warm air out to all the registers. If the system was designed and balanced properly, that means you get the right amount of heat in every room and everyone is comfortable.

Thanks for all the suggestions. I'll try to do the sealing myself first. If it doesn't work then I'll call someone to come to fix it.