We have been duct sealing manufactured/mobile homes for years and have had great success. We are getting more and more requests to perform whole house air sealing in these homes. I find that newer homes are already tight, and the older homes, well it seems we are just moving the leaks around. With duct sealing we can almost always make significant reducitons, but reducing house infiltration has been much more challenging.
Much of the challenge is that the actualy air barrier in the floor and ceiling planes are not readily accessible. Most mobes have do not have an accessible attic, and the floor is hidden by the road barrier (belly board). The simple areas like interior plumbing penetrations are hidden by cabinetry. I really don't want my crews cuting into the bottom of cabinets and the opening up the belly to foam these spots. Maybe that's what it will take though. We have also tried foaming the marriage line in double wides, but usually see little reduction.
Anyone have some good areas that can be reasonable accessed to seal?
Zach - those are some good questions and I am going to relate what they taught here in a DOE based Weatherization course & some of my own experiences (non DOE weatherization). For more info on DOE & Mobile Homes I suggest you check out this article I did: http://blog.sls-construction.com/2010/weatherization-program-modula...
Because of the way newer mobile homes are built, they could actually be better performers than a traditional house but aren't because of time constraints & older practices they still use during assembly. Unfortunately as you point out the penetrations caused by their practices are not always easily accessible. One of the best way of finding & sealing them is to run the blower door after taking care of the ducts @ 25 pa.
Plumbing - One trick I have used is to simply pry the escutcheon plate back, insert the tube straight down with the pipe & foam that hole up completely & trim the excess off before resetting the plate. Some of their bathtubs have access panels on them or in the next room to access the plumbing which can allow one to use whatever one needs to fill up that spot.
Kitchen & bathroom cabinets - caulk &/or foam them to the walls
Ducts - I am sure you either buy or create your own boots to slide in there and help eliminate that gap around them
Misc bathtub / electrical penetrations - For the electrical panel & the bathtub holes you might not have been able to get to before, you will need to access those from underneath & foam. Many mobile home companies sell patching materials for the holes you are sure to find under there & ones you create. One word of caution - don't use tape to seal them up - I recommend a mix of mastic & staples.
Rubber, foam or caulking for gaskets & weatherstripping - electrical plates, access panels, doors, windows, etc...
Once your air sealing work is done - then it is time for insulation (DOE recommendations)
Underbelly - make sure it is attached properly & patched - fill cavity with blown in fiberglass by using tube, extensions, etc... by slicing a small access slit every 10 feet or so down center - patch when done
Walls - drill hole with hole drill from interior & dense pack with cellulose & reinsert plug
The roof - depends on the roof, but for the metal ones they either drill holes every 4 feet or so, or peel the roof up at edges - dense pack cellulose & seal up hole / edge They generally top the roof off with a real thin layer of that white trailer paint, but the amounts they generally specify doesn't cut it --- Shingle roofs - up near ridge peel up a shingle tab drill through with hole saw, dense pack, reinsert plug & tar the crap out of area
Removing drawers in vanities allows access to holes that will be invisible when the drawer is replaced.
There is a fantastic road barrier repair material that is sticky on one side. Using a heat gun it fuses to the barrier. I forget what it is called but that stuff is great.