SEALANTS AND CAULKING:
"WHERE AND WHAT TO USE?"

GOAL:

To become familiar with the different types of caulking/sealants that are available in home construction.

OBJECTIVES:

The student will:

1. Compare the different types of sealants available and select the best one for a particular situation.

2. Determine areas which need to be caulked or sealed to prevent air infiltration.

LESSON/INFORMATION:

Infiltration of unwanted air assumes a leading role in calculating the amount of heat loss/gain in a building. It is almost impossible to completely seal a house. The fact that man needs oxygen to survive is a good reason for this impossible task. However, if we are to conserve energy we must do a better job of sealing the house.

Sealants work much better when applied during construction, rather than as an afterthought in conventional construction practices. Every possible joint between two materials which penetrates the exterior wall, ceiling or floor should have a sealant applied. There is more to sealing than smearing messy beads of caulking over everything.

In addition to sealing materials being used during the construction of the building, some sealing may be retrofitted in homes that have been built for many years.

Examples of this type of sealing: (1) sealing installed between door jambs, (2) sealing at the bottom of a door, (3) adding storm windows over existing windows, and (4) sealing receptacles and switch outlets in the interior.

Many caulking compounds can be found on the market today. One should pay attention to the manufacturer's description of the material, its performance quality, and directions for application. Use a compound that will adhere to wood, glass, metal, plastic, and masonry since these materials expand and contract. Also note weathering characteristics, such as cracking, shrinkage, water and mildew resistance.

Always use a good caulk gun with an automatic release. It is well worth the extra money and will be less messy. The automatic release stops the flow of material when pressure is released. All areas to be sealed must be cleaned to ensure good adhesion. Caulk must be sent to the bottom of the opening so there will be no bubbles. Don't skimp. If caulking shrinks, reapply to form a smooth bead so as to seal completely.

EXTERIOR CAULKING AREAS:

All joints between chimney and siding, eaves and gable molding, window sills and siding, window sashes and siding, windows and masonry, door frames, masonry and concrete parts, and inside corners formed by siding should be caulked. Perhaps the most important area to apply caulking is the area where the sole plate meets the slab. It is here that over 25% of air infiltration enters into the home, if this area is not properly caulked.

INTERIOR CAULKING AREAS:

All areas should be caulked such as around pipes, wires, vents, duct vents, between fireplace and walls, windows, baseboards, furdowns, built-in cabinets, inside closets, and outlet and switch plates.

TYPES OF SEALANTS:

The key to finding the correct sealant lies with the education of the user of these products. Many products on the market today either work very well and are expensive or work for a while and are inexpensive.

1. Mono Caulking Compound: a very sticky, acrylic-type sealant which works well. It does, however, have an unpleasant odor that lingers for days until the solvent evaporates. Cleans up with mineral spirits or naphtha. Moderately priced.

2. Silicone Caulking: a very good sealant which remains flexible after curing. It has excellent adhesion properties but cannot be painted. Exhibits little or no shrinkage and may be cleaned up with mineral spirits or naphtha. Expensive.

3. Latex: very easy to use; can be trimmed or smoothed with moist tool or finger. This material may be sanded and painted and is very water resistant once it is dry. Clean up with water. Moderately priced.

4. Oil Based Caulks: readily available, good exterior sealant. This material does have a tendency to become dry, separate, and fall from crevices. Clean up with mineral spirits or naphtha. Inexpensive.

5. Butyl Rubber: used to seal dissimilar materials (glass, metal, wood, concrete). It may be painted. Some shrinkage will occur and must be applied in warm temperatures (above 40degrees F). Cleans up with mineral spirits. Expensive.

6. Polyurethane Foam (Foam Sealant): may be used for filling large interior wall cavities with cracks that are open to the outside. It is somewhat difficult to apply in correct amounts due to its rapid expansion. The excess may be scraped off with a putty knife. Somewhat expensive.

The illustration below indicates areas to be sealed to prevent air infiltration.

Illustration courtesy of SLEMCO, from page 43 of their Design One Builder's Guide. 1988.

1. Caulk the sole plate.

2. Caulk or tape exterior sheathing joint.

3. After windows and doors have been installed, foam seal or caulk the space between the rough framing and the finished door and window (jambs).

4. Foam seal any gaps after electrical and plumbing penetrations are completed.

5. Foam seal or caulk all duct registers in the ceiling and wall areas before applying plates.

6. Fiberglass house wrap around the perimeter of the house.

The following list was originally used for a crossword puzzle. See if you can figure out a word that means the same for each.

1. Unlike

2. Washes with water

3. Single, solo

4. Cellular, compressible

5. Used to seal dissimilar materials

6. Capable of withstanding moisture

7. Used as a solvent

8. Good sealant, cannot be painted

9. Used to control moisture

10. Doubles in size

11. Associated with some foam sealants

12. To change into vapor

13. Having petroleum used in it

14. To make water tight

ACTIVITY 1:

Match the correct caulk with the correct job.

A. Silicone Caulk

B. Butyl Rubber Caulk

C. Latex Caulk

D. Oil-Based Caulk

E. Polyurethane Foam

____1. Joints between kitchen and bath fixtures.

____2. Seals most dissimilar materials.

____3. Joints around tub and shower.

____4. Exterior seams and joints.

____5. Difficult to use because it expands rapidly.

____6. Can be cleaned up with water.

____7. Cannot be painted over.

____8. Sometimes drys out and falls out.

____9. You can use your finger with this.

ACTIVITY 2:

List all exterior and interior areas that need caulking:

Exterior:

Interior:

INFORMATION CHECK:

Read each statement carefully. Which statements would be true ("T") and which will be false ("F").

1. One should use a silicone sealant to seal dissimilar materials.

2. Butyl rubber is recommended for use because it cleans up easily with water.

3. Oil base caulks are among the more costly sealants.

4. A caulking gun is not useful when wanting a neat and exact bead.

5. It is better to skimp on sealants than use too much.

6. Areas that should not be caulked are concrete parts and sole plates.

7. Sealants work best when applied after construction.

8. Latex sealants may be sanded and painted.

TEACHER'S NOTES:

Suggestion: Bring different types of caulking sealants to class. Allow students an opportunity to work with each type of sealant. Have dissimilar materials available.

Calculate the cost of a job using different types of sealants.

ANSWERS TO LIST:

1. Unlike = Dissimilar

2. Washes with water = Latex

3. Single, solo = Mono

4. Cellular, compressible = Packing

5. Used to seal dissimilar materials = Butyl

6. Capable of withstanding moisture = Water Resistance

7. Used as a solvent = Naptha

8. Good sealant, cannot be painted = Silicone

9. Used to control moisture = Sealant

10. Doubles in size = Foam

11. Associated with some foam sealants = Polyurethane

12. To change into vapor = Evaporation

13. Having petroleum used in it = Oilbased

14. To make water tight = Caulking

ACTIVITY 1:

1. = C -- Joints between kitchen and bath fixtures.

2. = B -- Seals most dissimilar materials.

3. = C -- Joints around tub and shower.

4. = C -- Exterior seams and joints.

5. = E -- Difficult to use because it expands rapidly.

6. = C -- Can be cleaned up with water.

7. = A -- Cannot be painted over.

8. = D -- Sometimes drys out and falls out.

9. = C -- You can use your finger with this.

ACTIVITY 2:

EXTERIOR CAULKING AREAS:

All joints between chimney and aiding, eaves and gable molding, window sills and aiding, window sashes and siding, windows and masonry, door frames, masonry and concrete parts, and inside corners formed by siding. Perhaps the most important area to apply caulking is the area where the sole plate meets the slab. It is here that over 25% of air infiltration enters into the home, if this area is not properly caulked.

Note: Be aware of the dissimilar materials being caulked on the exterior of the building.

INTERIOR CAULKING AREAS:

All areas should be caulked where pipes enter and vents exit, around duct vents, between fireplace and walls, around windows, baseboards, furdowns, built-in cabinets, inside closets, and around outlet and switch plates.

INFORMATION CHECK:

Answers to True/False:

1. True

2. False

3. False

4. False

5. False

6. False

7. False

8. True

REFERENCES:

SLEMCO's Builder's Guide - Design One Homes - for Energy-Efficient Construction. SLEMCO. 1988.

Comments or questions to: TechAsmt@LA.GOV

Return to Carpentry Menu