Caulking is a year-round job. In the spring, you caulk the exterior to get it ready for painting. In the summer, you re-caulk tubs and showers that mildewed during the winter and spring. In the fall, you find yourself caulking windows and doors and other potential sources of winter air and water leaks. Finally, during the winter when the ceiling begins to drip, you stock up on caulking for the roof.
There are three basic types of caulking--silicone caulk, butyl caulk and latex caulk.
Silicone Caulk The most expensive of the basic three is silicone caulking. It is best for sealing metal, glass, tile and other smooth, non-porous surfaces. Of the three, it is the most flexible and shrinks the least. Silicone is especially well-suited for sealing dissimilar materials.
Be careful. Silicone is not meant to be used on masonry or stone and doesn't do well on redwood or cedar. Most silicone caulks can not be painted, and because acetic acid is the solvent that keeps them damp, silicone caulks have a sharp, irritating smell.
Butyl-Rubber Caulk This group of caulks works best on concrete, concrete block, brick, stone, gutters, flashings and chimneys. What makes butyl caulk special is its ability to be used in extremely wet areas. This makes it great for jobs underground and on the roof. Butyl caulk also works well on aluminum siding.
Although butyl caulk can be painted, it comes in many colors. Unfortunately, it is difficult to work with. It is stringy when applied, requires paint thinner at cleanup time, shrinks a lot and is slow drying.
Latex Caulk The most popular of the three is latex--or acrylic--caulking. Latex is water soluble and that makes it easy to use and easy to clean up after.
It is best used on highly porous surfaces such as wood. Since latex caulk is used on both inside and outside surfaces, it is available in an interior and an exterior grade. The exterior grade is a bit more dense and therefore slightly more expensive. Exterior grade latex can be used inside, but interior grade is not for outdoor use.
Tips for Use When caulking, remember that the width of the bead will be about 30% wider than the diameter of the hole that you cut in the end of the caulking tube. Start with a small hole. Run a test bead on a scrap of wood. Enlarge the hole at the end of the tube with a razor knife, a little at a time, until you get the desired bead width.
It is important that caulking touch on three sides--the bottom and two sides--of the groove being caulked. Each surface helps to hold the caulking in place. If a groove is deeper than a quarter of an inch, we recommend that you use a foam backer rod, string, cloth, paper or some other flexible filler as a base.
Caulking requires a very important tool--your finger. And lots of paper towels or a damp sponge.
Vent, Fan May Solve Dripping Problem
Q: I am a building contractor and I am perplexed. A customer of mine has observed a strange phenomenon--small droplets of water have appeared along the underside of a ridge-beam above the family room. The moisture seems to be emanating from the rafter-bays immediately above this area. The rafter space is not well-ventilated and thus holds a great deal of heat. By mid-afternoon water drops can be seen beginning their descent. So, apparently the heat is the mechanism by which the water is produced. Do you have any ideas? What is causing this?
A: You have described the cause and effect beautifully. All you missed was the solution--and that's easy.
First, we must assume that the problem you have described is condensation and not a roof leak.
Normally, condensation is controlled by increasing the rate of flow of air in the area where the water droplets materialize. Since the rafters are not well-ventilated, this is the area that should be attacked. General Aniline Film Corp. (GAF) makes a product called Cobra Ridge Vent. The ridge shingles are removed, a slot is cut in the roof sheathing below, the ridge venting material is rolled out and stapled in place and the ridge shingles are returned to their original location, but over the new venting material.
A decorative light fan should be added to the ceiling of the room where the problem exists as an added precaution against a recurrence of the dripping condition.
* Cut the nozzle of the caulk tube at 45 degree angle
* Hold the gun at about a 45 degree angle, the same angle as the cut on the nozzle of the cartridge.
* An electrical wire nut will prevent partially used tubes of caulk from drying out.
* Caulk hard to reach places with an extension tube made from plastic tubing. Silicone--Use on:
Metal, glass, tile; smooth and non-porous surfaces
* best flexibility
* little shrinkage
* joins dissimilar materials
* can be applied at most temperatures Butyl/Rubber--Use on:
Concrete block and brick; gutters, flashing, chimneys
* used below grade and high moisture areas
* paintable and comes in color
* excellent for aluminum siding
Wood sidings; around windows and doors
* easy to apply; cures fast
* paintable and comes in color
* water cleanup
* good for interior caulking
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