Caulking and Glazing
Types of Caulking
Caulking may be classified by the material make-up or by the life expectancy. I will classify it by material and add some useful information.Oil Base Asphalt Caulk: You can expect this type of caulk to last 1 to 4 years. It is a soft and tar like material that may be used in seams and gaps on the roof, around chimneys, stacks, and pipes. It is useful for gaps up to 1/4". It hardens rapidly and tends to crack.
Latex Caulk: Lasts 2 to 10 years. It offers convenient clean-up (just water). It is intended for use in seams, cracks, gaps. It should not be used if expansion or contraction is expected (it usually is). Gaps should be no more than 1/4". Most latex caulks can be painted over. It is also available in colors. The biggest advantages are ease of use and clean up. If you (like me) smooth the joints with a finger, the clean up is a big deal.
Butyl Rubber: Lasts 8 to 10 years. It has some shrinkage and is commonly used in seams, cracks, and gaps up to 1/4". It is available in many colors.
Acrylic Caulk: This is one of my favorites. It can last up to 10 years and features easy water clean up. It is for use in seams, cracks, and gaps up to 1/4". It goes on easily and has no offensive odor (not like silicone). It is available in many colors.
Acrylic Latex Silicone Blend: It lasts 12 to 20 years. It is easier to apply than the rubber caulks. It can fill seams, cracks, and gaps up to 1/4" (This ¼" is getting familiar). It may or may not take painting depending on manufacturer.
Silicone Rubber: It lasts 12 to 30 years or more. It will adhere well in seams, cracks and gaps up to 1/4" as long as the gaps are clean. Paint does not work well on pure silicone. The manufacturer must use additives to allow for painting. Read the labels carefully to determine if your chosen brand can be painted. It is available in many colors and clear so maybe the painting won't be a problem.
Notice that the above products are for small gaps (up to ¼"). If you need to fill larger gaps, the following products may help but are intended for temporary use.
Caulking Cord: It is usually considered a temporary weather-stripping product and lasts 1 to 2 years. You will usually find it on a roll. As it is unrolled, it is simply pushed into place. It is useful as a temporary filler around storm doors and windows and air conditioners. The unused portion of the roll can be stored for long periods of time.
Oakum: It is twisted hemp treated with tar. It is cut to needed length pushed into place. It is used to stuff large gaps and caulking can be used over the oakum.
Glazing
Glazing Compound can last indefinitely when properly applied. Application requires some practice with a putty knife, and is used as a seal between the window glass and frame. It can become brittle and crack over time. Don't forget about glazed areas when thinking about repairs or maintenance. Linseed Oil Putty was used before glazing compounds but has basically been replace recently. It is harder to work with, offers less adhesion and cracks faster.
Where to Use Caulking
A 1/8 inch opening around just two door frames can let in as much cold air as a 12 inch window opened 6 inches all winter long. Unfilled gaps and cracks in the foundation, around windows and doors, vents, and so on, let winter cold air and summer heat in exactly the same as leaving a window open. Caulking is used to lessen these problems around outside window and door frames, and to fill outside wall and foundation cracks. The money you spend on caulking is usually recovered in one heating season or less. Some weather stripping materials are also useful.
A clean joint is the first and most important step. Clean away all old caulk and loose paint or dirt and apply new caulk to dry surfaces. The most common and easiest to use caulking comes in cartridges for which you will need a caulking gun.
A good rough estimate is that you will need 1/2 cartridge for each window or door, 4 for the foundation sill, and at least 1 more for around faucets, vents, pipes, electrical outlets and so on.
Cut off about 1/2 inch (less for small or narrow areas) of the cartridge tip on a 45 degree angle and puncture the tip seal with a nail. You can vary the angle for heavier application. The nail can be used later to act as a stopper for any unused caulk. A wire nut is also a good choice to stop the end. With a little practice on a joint that's not visible you'll soon be able to lay a uniform wide bead that overlaps both sides for a good seal. Finish the surface with a moistened finger if you like but that's not necessary. Remember to use a filler, like oakum, for wide joints before you caulk.
Before applying caulking compound
When surveying you home before caulking, some but not all the places you should look, are around doors and windows, dryer vents, faucet pipes and wires, where porches attach to the house, seams between masonry and siding, chimneys and inside corners. Clean area of paint build-up, dirt, or deteriorated caulk with solvent and putty knife or large screwdriver. Drawing a good bead of caulk will take a little practice. First attempts may be a bit messy. Make sure the bead overlaps both sides of the gap for a tight seal. A wide bead may be necessary to make sure caulk adheres to both sides. Fill extra wide cracks like those at the sills (where the house meets the foundation) with oakum, glass fiber insulation strips, etc.) In places where you can't quite fill the gaps finish the job with caulk.