Home>Discussions>INSULATION & HVAC>Adding insulation to existing loose insulation under attic floorboards in old house
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MJMathews
Adding insulation to existing loose insulation under attic floorboards in old house

I own a 1900 Victorian farmhouse located in Maine on the central coast. I have just put on a new roof and now want to improve the insulation. The existing insulation under the attic floorboards is a loose gray colored wooly material. It comes up to about 1/2 the floor joist level. Can I add additional loose fill insulation on top of it and then replace the floor boards? Or would I be better off removing the old loose fill and replacing it with roll out insulation?
The attic runs the full length of the house and includes single double hung windows on the gable ends and 2 pairs of double hung windows on the south/west side. It is about 12 feet high at the ridge.

MJ Mathews

dj1
Re: Adding insulation to existing loose insulation under attic floorboards in old hou

Either option will increase your R value and will be better than what you have today.

dgaynes
Re: Adding insulation to existing loose insulation under attic floorboards in old hou

A followup question: I just bought a 1920's colonial in Suburban New Jersey and need to insulate in a way very similar to the original post. My plan is to pull up the floorboards and fill between the joists with rollout insulation... Any advice from the community on whether it's advisable to replace the original floorboards after insulating or is there a better way to re-install the flooring after the job is complete?

MJMathews
Re: Adding insulation to existing loose insulation under attic floorboards in old hou

I had the same question in mind as dgayne, regarding what to do with the floor boards in my attic after insulating. I am replacing the original floor boards where possible, and substituting new floor boards where necessary. I concluded that the majority of my floor boards are in good enough shape to be reused. In some cases I have had to trim the old board, and add in a new board next to it, in order to get solid flooring.

As for the insulation, I decided to back fill with more loose fill under each board, except in the eaves where I used roll-out batting to prevent loose fill from falling into the eaves and blocking circulation. I also decided to add knee walls along the length of the attic on both sides.

Mastercarpentry
Re: Adding insulation to existing loose insulation under attic floorboards in old hou

You can reuse any sound materials if you want to, but if you want a better flooring now's the best time to do it.

Phil

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