Is there an eco friendly removable caulk product out there?

Asked by Carol Gonzalez
Laguna Beach, CA

I just moved to a beach cottage and I just learned that the house does not retain heat. I have felt colder inside the house than outside. There are windows that have big gaps that caulk can fix; however, I don't want toxic fumes, and i do need to be able to remove the product so I can open the windows during the spring. thank you for your time


Cynthia Phakos

Answered by Cynthia Phakos

Los Angeles, CA

Koffka Phakos Design

January 6, 2012

From your question, it sounds like you are planning to caulk gaps where the windows meet the sash and the sill and you will need to remove the caulk when you open the windows.

  • This is a somewhat unconventional solution.
  • In our climate (I live in Los Angeles) it could be 80 degrees in January when you might want to open the windows during the day and then close them at night.

Repair the windows

A more conventional approach would be to have the windows repaired. If you are the owner of the cottage it would be a good investment; and if not you might suggest it to your landlord.

  • Q-Lon weatherseals with a polyethylene cladding can be installed to the sash and frame of the windows and doors to create a tight seal.
  • A kerf or groove is cut into the wood and a bulb like weather strip inserted into the groove.
  • The seals are not paintable but come in a number of colors. These can be easily removed for painting.
  • The polyethylene cladding will not release any toxic fumes in its finished state.
  • A professional would need to install this. A window and door distributor in Los Angeles recommended Knight Construction (at 1-818-894-2362) to do the work. You could also ask the manufacturer for other installers.

Removable sealant is a less expensive alternative

Should that be too expensive, you could install a removable sealant as you discussed. 

  • Latex and Acrylic caulks can be removed by simply pulling them up or cutting them out with a utility knife. These caulks are typically for the interior.
  • OSI’s Green Series Draft and Acoustical Sound Sealant by Henkel for interior use contains no formaldehydes.
  • I personally have not experimented with trying to remove it so if you should chose this route, first test it.

Other drafty leaks could be the cause of heat loss

With that said, there are many areas other than the windows that could be the reason that your house doesn’t retain heat. According to the U.S. Department of Energy,

"caulking drafty areas of a building can cut energy costs 10%; furthermore, about 50% of the average fuel bill is the result of heat loss from air infiltration. The energy efficiency of our houses can be vastly improved with the low cost method of caulking the drafty leaks of your house.”

If you decide to caulk exterior areas then a brand that I would recommend is SafeCoat’s Caulking Compound.  Their website states that

“It is a non-toxic, water-based, elastic emulsion type caulking compound designed to replace oil caulk and putty for windows, cracks and general maintenance work. It will not dry out or crack and does not release any solvents.”

It cleans up with warm water (as does OSI’s). You might experiment with this one as well to see if this is easy to remove. For both of these products, I suggest that you read the Technical Data on the manufacturer’s website for installation instructions. Below I have listed some information and a brief background on Sealants and Caulks.

Tips for sealing/caulking

Things to consider when sealing/caulking your home:

  • Caulks and sealants are usually applied in the same manner, with a caulking gun. You will also need a utility knife.
  • Clean surfaces so that the caulk will bond properly. Brush or vacuum joints. Adhesion failure is a common reason that joints fail.
  • Shape the caulking bead with your finger so that it has a concave shape. This will give the maximum surface area for adhesion with the center thinner and more flexible when there is movement in the joints.
  • As the building will be more water tight, take care not to trap water in the wall.
  • When caulking the exterior, do not to caulk the underside of window and door trim or clapboard siding. This will allow water that gets in, to get out.
  • For gaps deeper than 1/2” first insert a flexible backer rod (foam cording available at most hardware stores). Then fill to the surface with the caulk preventing cracking. Some products allow a max of ¼”, so review the specific technical data.
  • Don’t rely on caulk where there is shoddy workmanship. Trim and clapboard joints should be tightly joined. Use a paintable caulk, for areas that are visible.
  • In selecting an interior sealant or caulk chose a low- VOC product.
  • Seal and insulate the foundation walls of unventilated crawl space.
  • It the attic is not properly insulated then your sealing the cracks will not be that effective. The attic is the easiest place to insulate if you have a crawl space.

About Sealants and Caulks

The terms "caulk" and "sealant" are often used interchangeably, as they serve the same purpose; filling the gaps between building materials to minimize water and air intrusion.

  • “Caulk” was a term first used for a material that seals the space between the boards in boat building; whereas “sealant” was a term that originated in home building. 
  • Some manufacturers today use the term caulk as an all-purpose term and sealant to describe their high-performance products.
  • Other manufacturers use the term “caulk” for materials which are more rigid when dry and are used in areas where there is minimal expansion & contraction. “Sealant” then refers to a more flexible material.

In the past sealants and caulks were either pitch; a material made from plants as pine pitch, or bitumen; a petroleum-derived material. With the development of synthetic polymers in the 1930’s there is now an abundance of manmade rubber-like caulks and sealants. The polymerization process chemically links small molecules to make larger molecules, with the resultant molecules retaining properties similar to the original molecules.

Viscosity and elasticity

Two material properties to consider in the selection of a sealant or caulk are viscosity and its elasticity.

  • Viscosity describes a fluid's internal resistance to flow and is a measure of fluid’s friction. (Wikipedia) A material with a high viscosity has little to no flow with water considered to have a very low viscosity.
  • Elasticity or stretchiness allows the material to return to its original shape after the external forces that have caused the change have been removed. In the case of caulks or sealants the external force may be temperature, or load, such as wind or weight. (Wikipedia)

Five types of sealants and caulks

For residential installations there are five basic types of sealants and caulks:

  • Butyl; 
  • Latex;
  • Acrylic;
  • Silicone; and
  • Polyurethane (and their hybrid types).

Butyl is a polymerized synthetic rubber (polyisobutylene) that chemically resembles polypropylene, is a viscoelastic material, with good adhesion and is weather resistant and impermeable. On the negative side, it is stringy like gum and has a low elasticity. Also, it is difficult to get a good quality joint as it has an unattractive tarlike appearance.

  • Main uses: Repairing aluminum gutters; caulking aluminum flashing; filling cracks in asphalt; sealing siding around doors and windows. Good for below grade sealing.
  • Cleanup: Mineral spirits or lacquer thinner.

Latex is a viscous material made up of the polymerized microparticles in an aqueous medium. It is applied as a liquid and is typically water-based making it easy to work with. Latex has the least ability to stretch (7% to 10% elasticity) and works best for interior applications where little movement is expected.

Acrylic is a family of synthetic resins that are clear, water-soluble and easy to work with. It can be painted and so can touched-up and is goof for filling small gaps. Acrylics have a limited elasticity making them susceptible to cracking w/temperature change and drying out over time. Siliconized Acrylic caulk (Elastomeric) is a high-performance acrylic, w/greater elasticity and a market favorite.

  • Main uses: Utility caulking for nearly all interior and some exterior sealing.
  • Removal: Can be removed by simply pulling up or cutting it with a utility knife and then pulling.
  • Cleanup: Water.
  • Life span: 5-10 years depending on environmental exposure and building movement.

Silicone is a polymer formulated from silicone oils that can be combined so they will harden at room temperature. The hardening process releases an acetic acid as a by-product, which is an organic compound; the main component in vinegar other than water. Although it has a strong odor it is not toxic. It is non-porous and watertight even w/temperature fluctuations. Silicones are extremely rubbery with 50% elasticity. They adhere to non-porous surface but have poor adhesion to materials such as wood. They are difficult to apply and can’t be painted.

  • Main uses: Sealing around tubs, shower and sinks; caulking exterior trim; gutter repair; sealing or caulking against aluminum, glass and other nonporous materials.
  • Cleanup: Mineral spirits.

Polyurethane, a polymer of a glycol with an isocyanate, is preferred for outdoor applications. Polyurethane works well for filling indoor gaps in floorboards as it can take the high-traffic stresses of floors, though it is not necessary for other indoor applications. The material is hard to control and takes time to set up in situations where an acrylic latex would be perfectly suitable.

Polyurethane has a tremendous bonding ability and so it can be used as an adhesive in some cases. Its removal can be difficult and it usually involves cutting out or sanding. It can be painted. Polyurethanes are solvent-based and is potentially hazardous to your health. Cleaning up requires solvent or paint thinner. Use rubber gloves and a respirator when applying it.

  • Main uses: Sealing control joints in concrete; repairing cracked masonry; exterior caulking around windows and doors; repairing cracked vinyl siding; bridging gaps between porous and nonporous materials.
  • Cleanup: Mineral spirits.
  • Life Span: 10 – 20 years

Latex Acrylic Hybrids for enhanced performance. Acrylic Latex Hybrids with Butyl for greater strength. Silconized Acrylic Hybrids offer greater elasticity and a paint-friendly surface for an indoor setting where flexibility is critical.

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