Hi all,
I just installed a deck to the back of my house and now need to install a patio door where there was a window before. The same area of the house has old T1-11 siding that is in bad shape. Underneath the siding that I removed already was a black fiberglass? looking sheathing/insulation.
I’m looking to take down the old siding and put up new T1-11. Should I install a tyvek housewrap along with foam fiberglass board underneath the new T1-11? Or should I install only one or the other? I live in Maryland where the summers can be really hot and the winters can be really cold? Any help would be much appreciated.
Thanks,
Brian
Replies
If this is a house built somewhere from the 50s through the 70s then the black sheathing is likely a sort of paperboard product. It is surprisingly strong and not a terrible insulator (though it's hopefully not the only insulation in the walls), and need not be replaced if it's in reasonable condition. Perhaps more to the point the stuff is a b!tch to remove if stapled on (which is typical).
If the stuff is of newer vintage then it may be a different product.
Tyvek won't hurt, though it should not be used in place of proper flashing around the new door.
what you have now is asphalt impregnated homasote, common for a generation. It was normal to use 1/2" plywood sheathing at corners, and this material in the field.
To replace, you can use just about anything that is 1/2"