Today we have two unrelated, but rather short questions. They will both be answered independently.
Will spray-on foam insulation adhere to plastic sheeting?
I read your articles every Sunday and would appreciate instructions on a proper way for teleposts adjustments. I plan on doing some interior painting, but have some cracks and want to avoid them after painting.
Looking forward to your reply,
The answer to the first question is a simple yes. Spray-on foam insulation will stick to just about anything, often things you don’t want it to. Most spray-on foam insulations available at the retail level are single component polyurethane compounds that come in aerosol cans and can be easily applied to any surface. These sealants have the unique property to insulate and air seal at the same time. Most are moisture and rot resistant, so they can be used in damp or below grade applications.
This type of insulation is ideal for hard to reach areas and locations that are too small for other insulation methods, of simply for filling holes. The foam expands to fill cavities, once released from its canister. The amount of expansion will vary with the variety purchased. For large open areas, foam sealant should be purchased that has maximum expansion, often 2 to 3 times its initial volume. Low expansion varieties should be used for small gaps around doors and windows to prevent bowing in of the jambs.
Like many synthetic products, expanding foam insulation will discolour and deteriorate with exposure to ultraviolet light. If left exposed on the exterior of the building, it should be painted or covered to prevent deterioration. Care must be taken when applying this product due to the high expansion rate. When curing, the foam may swell sufficiently to push on and bow door and window jambs, wall coverings and other building components. Cavities should never be overfilled to prevent this over-expansion. Curing rates vary with types, but most are easily trimmed with a utility knife, once hardened. This will allow for removal of excess foam that leaks out gaps after application.
Work clothes, gloves and eye protection should be worn when installing expanding foam insulation, due to the difficulty in removal of excess material. Anyone who has used these products can attest to the excellent adhesive qualities especially to skin and clothes. It is extremely hard to remove until cured and covering of furniture, carpeting, flooring or other household items should be done before installation.
Telepost adjustment can range from being a relatively simple procedure to one that is very complex, depending on the house in question. Older homes with simple rectangular floor plans may have a single main beam with one or more teleposts. Newer homes with multiple floors and levels may have several beams, with many teleposts of varying heights and locations. Often these structural components are hidden inside basement walls and ceilings, making measurements and adjustments difficult.
Teleposts are steel columns located under beams on the lower level of homes to support the beams and floor structure of the house. These posts rest on the footings beneath the basement floor slab. Teleposts are designed to be adjusted to accommodate movement in these footings due to soil settlement and seasonal expansion and contraction of the clay soil, in our area.
Determining the location of the beams and teleposts in a home is the first step in any adjustment. If your home has a very simple floor plan and the beams and posts are open for view and not covered by walls or ceilings, adjustment may be relatively easy. If the beams are hidden in finished ceilings or the floor plan complex, a professional foundation contractor or structural engineer should be hired to provide a plan of action.
Homeowners often talk about “levelling” a beam by telepost adjustment, but this description is not accurate. What should be attempted is to maintain as straight a beam as possible, with little concern about level. Most homes in our area will settle in one or more directions, which makes levelling the beams impossible. Maintaining a straight main beam will prevent bumps in the floors above and minimize cracks and movement in the walls.
If the beam is wide open and visible at either end, often straightness can be determined with a very tight string suspended down equal distances at either end of the beam. Measurements can be taken from the string to the underside of the beam, above the teleposts, and the difference between this distance and the space at the ends of the beam is the amount of adjustment required. This adjustment is most often required in a downward direction. Allowance should be made for slight sagging in the string, as well.
Adjustment of the screw heads of the teleposts can then be done very slowly, with a wrench and hammer, as required. Care should be taken to adjust each post very slowly, with no more that ¼ turn per adjustment. These adjustments should be spaced apart by a number of weeks, as well. Slow adjustment in this manner will minimize stress to the building and prevent new cracks developing in the walls, due to the movement in the floor structure. Telepost adjustment should never be attempted in a single shot, or significant wall cracking and damage may occur.