Adding insulation

[CTyler]

I have a pole building that was insulated when it was built. The insulation is fiberglass with a white reflective(?)backing. Not really sure if it has a reflective value for insulating vs just reflecting light better.

I framed off a 50x16x8h area that is to be finished. There is a utility room with a toilet, shower, laundry. I want to add additional insulation to this whole area.

The part that has me concerned is the existing white backing/reflective layer on the outside walls. The vapor barrier should be to the warm side of the building(inside). By adding additional insulation this will place that layer in the middle vs the inside. Do I place some slits in it and add a new vapor barrier or just add insulation? I don't want to trap moisture and cause problems down the road.

I'm making the assumption that the backing is indeed acting as the vapor barrier.

Thanks
Chris

 

[Glenn9643]

I built a house in 1975 using styrofoam sheathing on the outside (behind brick) and 6 mil poly on the inside of the walls and ceilings. This had the effect of a vapor barrier on the inside and outside of the wall. I've not had any ill effects. At the time there was some discussion in the building trades about possibility of condensation being a problem, but they're still building that way around here.

 

[ikline]

I use to install and sell insulation. When we ran into a project like this we would just remove the Vapor Barrier (should just peal off), add more insulation with a Vapor Barrier or seperate vapor barrier. If you don't you could have problems. I have seen attics where they laid insulation on top of each other with vapor barriers between and had no problems and I have seen it with lots of mold. Better safe than sorry.

 

[CTyler]

Thanks for the replies.

I talked to Cleary and they said they just add unfaced insulation and haven't had any problems. He said they leave the top of the wall open. Guess that depends on how you frame it out. I'd have to drill holes in the top plate.

Peeling off the backing, insulate and putting up plastic sounds like it might be the plan.

I'm curious if you remember there being a difference between the moldy vs not moldy install? For example the moldy insulation had no gaps at the end to it breath some. Or if there was no vapor barrier on the insulation for the last 1'.

Thanks
Chris

 

[CTyler]

If I remember right they add weep pipes or wick between the brick and house to let the moisture out.

 

[SPIKER]

I remember this guy added plastic wrap (like 6 mil poly stuf not the right stuff.) his house lasted abotu 8 years then the OSB was ate by black mold and litterly would crumble away by a person leaning on the out side of the siding! hole house ended up being torn down and rebuilt. needless to say it has happened more than once.


they have to breath or else mold & rot will build up and it will be done for

Mark M /forums/images/graemlins/frown.gif