How to Retrofit Older Attic with Baffles?

Frankie1969 · 06-26-2012, 07:33 PM

Hi there, i am just a home owner who wants to fix an insulation issue, but need to fix the venting issue first. So i don't know all the construction lingo but will do my best to describe the problem.

My home does not have attic baffles installed anywhere in the attic. I want to install accuvent baffles as they look to be the best option on the market.

The home is a 1200 sq ft bungalow, with what I believe you call a hipped roof. I am concerned about how anyone can retro fit these? I just don't see how a normal sized guy can fit into that tight space to install the attic baffle?

Does a guy simple use some planks to lay on to prevent any accidents like a foot through the ceiling, and just slowly work your way around the home?

Can someone give me some guidance here?

cleveman · 06-26-2012, 11:57 PM

Frankie,

You are absolutely right about a normal guy not being able to do this job. You must seek out an abnormal guy to do it.

Don't try to do it when the weather is warm.

Get up there and see if the rafter chutes are clear. If not, clean them. Then you want to install the vent chutes and staple them up and fill the gap with something like fiberglass insulation, paper, plastic bags, etc.

When you clear out the vents, it may be very tight up there, so you want to give thw workers everything they need.

**Gary in WA** · 06-27-2012, 01:38 AM

Good advice! If in a cold climate, many times the older houses have 2x4 rafters with only 2-4" of room for insulation over the exterior walls. Use stacked-up thicknesses of foam board there, for the first foot or so to get closer to the R-value you need- leave the required 1-1/2" air space above it. Hope you have intake soffit vents... This will reduce the possibility of ice dams; http://www.extension.umn.edu/distrib...ng/dk1068.html

Air seal the attic first; http://bct.eco.umass.edu/publication...o-save-energy/

Find the air leaks: http://www.finehomebuilding.com/PDF/Free/021105092.pdf

Gary

Frankie1969 · 06-27-2012, 08:47 AM

Thanks GBR and Cleveman. I am in a very cold climate, and you are right that there is only 4" or so of room to move around, very tight.

So you have answered my question then, totally doable, just a tough dirty job. Thanks.

On another note, If I understand you correctly, your suggestions for foam board or filling the gap with another product is to prevent ice dams or from the wind from blowing the insulation away over that top plate off the exterior wall. I am by no means advertising here, but accuvent baffles are what I want to use, and one of the things I seen when researching them is that they stable onto the top plate, and then then roof. I think this addresses that issue.

wkearney99 · 06-27-2012, 10:49 AM

A roof over a cold zone needs to have outside air flowing under it. This keeps the underside of the roof close to the outside temperature. This is very important in winter because if the underside gets too warm it'll allow the topside to freeze, leading to ice dams and all sorts of potential damage.

So the idea is air flows up from openings at the outside soffits and then up to a ridge vent. Baffles can be used to allow insulating material to come closer to the underside surface without blocking the necessary airflow. They're not necessary if enough room is left in the rafter bays.

Yep, it's nasty, hot, dirty work. A sheet (or two) of plywood would help give you a platform to rest on instead of trying to balance on the ceiling joists. Wear long sleeves (or a whole tyvek suit) and a mask to avoid getting insulation in or on you (some older kinds can have asbestos in them). And be careful about heat exhaustion.

Neighbors of mine recently had their attic foam insulated and where astounded by how much their heating and cooling went down. The 50's era houses around here have pretty poor insulation. A previous owner had laid some added fiberglass but it was nowhere near as effective as the foam.

**Gary in WA** · 06-28-2012, 12:21 AM

You can use that product, in fact I have recommended it here for 3 years. Now I say foam board because the f.g., Roxul, etc. is only R-3.7 per inch, a whopping R-7 with the rest of the attic at R-49 or so. Right over the heat loss (exterior wall) with a vent block of R-1.25 per inch for solid wood. Either will stop wind-washing, f.b. will also insulate more per inch...... Add the almost constant convective heat deposit at the top of the exterior wall from f.g. cavity insulation, no wonder ice forms above there;http://findarticles.com/p/articles/m...6/ai_n8582994/

Gary