Q. I own a very old house that was never insulated. I want to insulate the attic but have received so many conflicting opinions from contractors that I don’t know what to do. Also, should I be concerned about the thickness of the insulation? Can you help?
A. All of the different insulating proposals you described in your message are legitimate. The important thing is for you to decide on a method and get the attic insulated as soon as possible, because you are losing a lot of expensive heated and cooled air through it.
In addition, if you insulate before the end of the year, you can qualify for a federal tax credit of up to 30 percent of the cost (maximum credit is $1,500). For more information on the tax credits, visit www.energystar.gov and click on the icon reading Tax Credits for Energy Efficiency.
My choice for insulating the attic would be either blown-in insulation or fiberglass blankets.
Blown-in insulation, usually cellulose, has a slightly better R factor or insulating value per inch than fiberglass. It will put a thick blanket of loose granules over the attic floor.
It is important to select an experienced contractor to ensure a uniform thickness and good coverage.
Fiberglas blanket insulation, which usually fits between the floor joists, is somewhat neater than blown-in and should give uniform, effective coverage.
One type of fiberglass insulation is wrapped in perforated plastic, which helps keep the insulation clean and prevents fiberglass particles from getting into the air. Wrapped insulation is a good choice if you want to use part of the attic for storage.
Foam insulations such as Icynene can also be used in attics. These are generally sprayed on the underside of the roof and are best suited for attics that will be used for living space.
This option definitely requires an experienced installer and generally is more expensive than floor insulations.
The thickness of insulation is important because it will determine how well it will insulate and cut your heating and air-conditioning costs.
A minimum of R-30 insulation, equivalent to about 10 inches of fiberglass or cellulose, is recommended for all climate regions of the nation. In very cold climates, even more insulation is recommended.
An experienced contractor will know how much insulation is practical for your attic.
If your house has an unheated basement or is built over a crawl space, you should also have the ceiling over that space insulated. Old, drafty windows are another source of high heat loss.
Q. I have a painted brick fireplace that I want to cover with ceramic tiles. Will the latex-modified thinset mortar you recommended recently for a tiling project work with painted bricks?
A. Thinset mortar or adhesives will not work well on a painted surface. Essentially you would be fastening the tiles to the paint, not the bricks, and if the paint comes loose so will the tiles.
The best bet is to remove the paint or first cover the bricks with cement backer board to give a fresh surface. Cement board would have to be fastened in place with masonry screws or similar metal fasteners, not adhesive.