On Monday, I inspected my crawlspace because of a mouse problem. When I was in the crawl space, I found an incomplete repair of the HVAC system. From the builder, I learned after closing there had been a problem with a duck in the crawlspace that died in the ductwork and was eventually removed and damaged items were “repaired”. When I did the inspection for the mouse problem, I found uncorrected damage, pictured here.
So, with a couple of assistants out of school for the week (my 7 and 5 year olds), we took our supplies and went under the house. Upon further inspection and preparation, we also found a disconnected duct to the utility room, an area always difficult to heat and cool since it was not getting any air. So, we set to work on the two repairs. First the hole, then the disconnected duct.
To fix the hole in the trunk line, I began by covering the entire hole with foil tape (UL 181 tape, the same type used for Energy Star Homes). With the hole covered, I wrapped the trunk line, including a previous repair, with duct insulation and completed with foil tape to secure it to the trunk line and seal off any holes/leaks.
The disconnected duct was easily repaired as well. After cutting the end of each line, the two ends fit more closely together. With the foil tape and a little maneuvering, the two lines came nicely together. As I was completing the repair, the air turned on in the house and I was able to check the reconnected line for leaks. While checking, I noticed several other ducts where the duct tape had deteriorated enough to allow air to freely flow from the seams. I resealed those with foil tape as well (if I had mastic – a sticky sealant that will seal the lines air tight – it would have been an easier fix).
After a few more tests and cleanup below the house, the crawlspace was as good as new and will be a little cooler next time I go down there.
I also completed the insulating foam on the attic stair. This will reduce the amount of air loss around this opening.
Next article will discuss indoor sealing techniques.