Insulation drifts

Inspecting a new two story townhouse style condo, the blown in fiberglass insulation was blowing all about. It was piled up in drifts and had blown off the ceiling in various spots throughout.

It was pretty breezy in the attic as well. Perforated metal soffits and at least four static ventilators in the upper part of the roof. Not going up on that roof it is covered with snow :slight_smile:

I reported it to the builder. I am doing two more tomorrow, so it will be interesting to see what I find in the others.

The exterior is finished as in siding roof etc., the units are located in a new development on the edge of the city and are very exposed.

I promised the owners I would come back in a month to see if all was OK.

Anybody seen this before? Suggestions on how to prevent?


I think it’s probably more to do with poor installation. There are still bits of insulation on top of the trusses.

If it was due to wind, I don’t see why it would blow through certain truss spaces and not others, unless the baffles don’t block off the space between the baffle and top plate.

I went back to do the other two today and found the same thing, but not as severe as the first. I spoke to the guys on site, there was a big wind storm here a few weeks back, and they told me that some of the soffits had not been installed when it blew in. So the insulators are coming back…
I also think there is something to what Lee said. Is there a way to adjust insulation fluffiness? Does the blower shred it or puff it up? This stuff was like cottonwood or poplar fluff like we get here in Spring. Never seen it that loose before.

I see that routinely. The batts used as baffles get blown out and the loose fiberglas insulation gets piled up like a snow bank.
Not so much with loose cellulose fiber.

Yup! It is wrong each and every time…

I see this regularly in new construction.

The insulation is installed before the soffits are installed and the wind blows it around.

It also happens after the house is finished. The fix I like is baffles installed and the eaves sprayed with closed cell foam, then insulation installed.

As far as the best construction for energy efficiency, a platform at the attic level with the roof structure on top would avoid those problems and insulate better as well.

You should also check if any of the HVAC Ducting has any tears or improper connections. When the AC Starts you would be amazed at the Air Dynamics of Leaking Duct Work.

Check for Duct Work Leaks (Poor Connection, Missing Duct Tape, Tears in Ducting. Air Dynamics in an attic with faulty ducting and Gable Air Exchange can create loose insulation pile ups. Check the Ducting.

It’s called wind washing. It has noting to do with how the insulation is installed. If you think it is too fluffy then ask for the insulation certificate and see if the height it is installed is equal to the number of bags required by the manufacture for the same size attic. The baffles are there to prevent this and I have even seen it under o’hagan vents. If it keeps happening then they can try and install a longer baffle or put a batt there and fill the blown in around it.

Yep, O’hagin vents and loose fill fiber wool don’t mix well…snow piles.

They need to add some type of glue to the fiber when installing-spraying. I recommend spraying some Cellulose on top of existing when I see this OFTEN at new construction.

We have some bizarre wind storms during the monsoon season, creates havoc to wool.

You can also install a dam, heavy cardboard or rigid foam, at end of ceiling joist with baffles setting on top, actually extending a couple of inches over the edge of dam.

Here’s a nice link: Click Description.

No HVAC attic ducting in Alberta.

Not completely true. There are insulated exhaust ducts up there. The new ones blow pretty good too, not like the old school 50 cfm fart fans, whole house fans may be on 24 7.

I just saw ‘wind drift’ on a home located on a corner lot. I thought maybe it was just the extreme force of the wind passing across the corner and disturbing the blown in insulation. On closer inspection the air chutes were missing in two of the soffit feeds. Insulation pile looked like sand on a beach when is slowly gets all shifted to one spot and you can see the layers of settlement. Very interesting.