"Replacing siding and windows"
Column #806 07/31/10
On The Level
Q. I have a old house that I bought that has aluminum siding on it that I may need to replace since it has dents, been painted and may need to make a sliding glass door into a window. The house was built in 1983. In replacing the siding, I was wondering what type you recommend and also since the siding would be off, should I also do a wrap of the house or consider siding with some time of insulation. I have noticed a lot of homes that appear to have mold or mildew appearing on the siding. What causes this and when purchasing new siding is there something that I should consider so this doesn't happen to me?
A. If you are contemplating a complete residing project you have a great opportunity to really improve the way your house performs from a heating and cooling standpoint. You say you are thinking about removing a sliding glass door and replacing it with a window. While youíre at it take a very close look at the rest of the windows in that 27 year old house. I can tell you they are functionally obsolete.
Most windows are installed from the outside and are attached to the house framing by nailing through a perimeter flange that measures normally about an inch and a quarter that also doubles as flashing for the installation-- in a perfect world-- but it satisfies the code. Then siding, whatever it may be, gets installed and butted to the window edge which protrudes out an inch or so. Sometimes that seam gets caulked and sometimes not. If you decided to replace your windows and not the siding then getting those old windows out and the new ones installed well becomes a problem. But with the siding off the whole job just jumps out at you.
You hit the nail on the head about adding a house wrap. In 1983 a ďweather resistant membraneĒ was not required to be installed under aluminum siding according to the old code books I have. It would have been a good practice and products such as Tyvek by DuPont were available but most didnít use them unless they were required. You could find a joint in your siding and slip a putty knife under the siding and lift it out a bit to peek but Iíll bet you wont see any. Back in the day prior to the requirement of house wrap houses were framed, as they are today, in a manner called platform framing. The framers frame the floor, which becomes a platform, then frame and stand up walls on that platform and so on until itís time to put on the roof. The bottom edge of the exterior wall frame as it sits on the floor was not sealed-- as it is today-- and air could and did get under the frame and into the house which is what was causing the dark band of dirt on light carpets that drove homeowners crazy until it was identified and named ďfiltration soilingĒ. House wrap installed properly, in addition to being a vapor retarder, prevents carpet soiling inside the house along those walls.
Do your homework on how house wrap is to be installed and how edges are to be taped. Window edges too are to be taped and in a set sequence of bottom, sides and top and be sure itís done right.
Siding selection is a function of taste and cost. Most folks want the outside of their homes to be as maintenance free as can be and today that seems to come down to either vinyl or fiber cement siding. Fiber cement is more expensive and harder to install but has its strong advocates. Google fiber cement siding to view the various manufacturers and basic pricing. Vinyl has many shapes, colors and price ranges and you can view an online design tutorial on the Vinyl Siding Instituteís website www.vinylsiding.org. Iíve seen both fiber cement and vinyl siding products that so closely resemble wood that I had to go up to it and touch it to tell the difference. Iím not aware of any algae resistant siding but a mild bleach and detergent solution takes care of that periodically.
While youíre at it, jump up in the attic and check the insulation. If itís original it needs upgrading to R-38 and thatíll be cheap to do. Then with new siding and windows properly installed and upgraded attic insulation your heating and cooling loads will be lowered and you can begin paying for the project little by little with lowered energy costs.
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