Button Up Your House’s Coat!

Gaps in caulk and weatherstripping that let cold air into your home is like leaving your coat unbuttoned in a snowstorm. So button up that coat, and get your house sealed before it’s too cold to do it!

Did you know that the average home has enough unsealed small openings to create a 2-foot square hole in the wall?!? Sealing these various gaps can save you up to 20% or more on your heating bills. Every home has intentional and unintentional gaps. Door and window openings are gaps created intentionally. Those gaps are filled with doors and windows. Gaps like cracks and air leaks in doors and windows are unintentional. Of all the ways to seal the unintentional gaps, the most common and DIY-friendly products are caulk, weatherstripping and spray foam. Caulk is a flexible material that is forced into gaps and cracks. Caulk cures and hardens, forming a seal, and is intended for use on surfaces that don’t move. For surfaces that do move, like doors and windows, weatherstripping is the correct product. Weatherstripping is made of plastic, rubber or sometimes metal. We won’t talk much about spray foam, but it comes from a spray can and expands to fill gaps.

This article from the U.S. Department of Energy on ‘Air Sealing Your Home’  at energy.gov is especially helpful.


There are many types of caulk that you can buy readily at the big box stores or your local hardware store. Temperatures need to be relatively warm to apply exterior caulk- anything below 45-50 degrees won’t allow the caulk to flow or adhere properly. For exteriors, latex caulk is easy to apply, takes paint well and cleans up with water, but has limited durability. Silicone is relatively easy to apply, is not paintable, and cleans up with acetone, but has much better durability. Some high-quality and long-lasting exterior caulks are Sashco Big StretchSashco Lexel, and OSI Quad. Latex interior caulks are easiest to apply, but won’t last as long as silicone. And again, latex is paintable, silicone is not. Higher quality caulk stretches more and is less likely to crack, and going cheaper means caulking more often.

Two products that are little-known but some of my favorites for interior use are DAP Seal ‘n Peel, and Mortite rope caulk. Seal-and-Peel is a temporary caulk that is good for large gaps in windows that will need to be able to move again in the springtime when you open up the house. It removes easily and won’t stain or mark. Rope caulk is a small bead of oil-based caulk in rope form that is also temporary, but so easy to apply. It doesn’t stain either. You can leave both products applied for the duration of the cold weather. They’re not meant to be used for more than one season, so don’t expect these temporary caulks to work long-term.

Using a caulk gun (instead of a squeeze tube) gives the best and most durable application. A dripless caulk gun is the most trouble-free. Technique is important when applying caulk with a gun. Many times you’ll see videos that show people dragging the caulk along the seam or opening. That’s not a good way to apply it- dragging the caulk leaves it on the surface, and the seal won’t last very long. The best way to apply caulk is to push it along the gap, forcing the caulk into the gap. Cut the tip of the cartridge to the size of the bead necessary to seal the gap in question, and apply the caulk at about a 30-45 degree angle. You’ll probably need to try it a few times to get it right if you’re not used to it.

It’s important to always remove as much old caulk as possible. Old product will prevent the new caulk from adhering and fully sealing.


Weatherstripping deteriorates over time, so it is important to inspect it every year before the cold weather hits. To check your weatherstripping, try closing a door or window on a strip of paper. If the paper slides easily, your weatherstripping isn’t properly sealing the opening. Alternatively, close the door or window, hold a lighter near the frame, and see if the flame moves (but don’t burn down your house!). There are many weatherstripping products that stick to door and window frames. Door bottoms should be sealed with a door sweep, and they make them to be installed on the back surface of the door, or the kind that is tucked underneath it. Use the paper or the lighter trick to check the seal.

Many older homes have single-pane windows with weights, and those are good candidates for rope caulk or Seal-and-Peel. You can also find pulley seals to close those big pulley gaps. Some older windows will have a metal weatherstripping called spring bronze. This is the single most effective weatherstripping I’ve encountered. Being bronze, it doesn’t corrode or rust from moisture. It is usually compressed from use, but don’t remove it! If it’s not torn you can carefully pry the metal back up and restore its ‘springiness’, allowing it to seal your windows once again. Spring bronze is a durable and excellent eco-friendly product (you can still get it but it’s pricey)- you don’t have to periodically remove it and throw it away.

Seal it up!

Here are the main places to seal your home:

1- Seal the exterior

Apply caulk:

  • Where 2 materials meet- siding to window, siding to foundation, siding to roof, siding to chimney
  • Cable and plumbing penetrations
  • Around windows and doors
  • Where window or door trim meets siding
  • Weep holes are the small openings at the bottom of modern vinyl windows- they let water out. Don’t caulk them!
  • Also don’t caulk the window bottoms- they’re usually left open to let out water that gets in on top.

2- Seal the interior
Apply caulk:

  • Around windows and doors Where window or door trim meets siding
  • Sill to edge sealing

Apply weatherstripping:

  • Windows- use caulk (non-moving gap) & weatherstripping (parts that move)
  • Doors- use caulk and weatherstripping
  • Electrical outlets are notorious for air leaks, and you can purchase special foam gaskets made for this purpose.They go under the cover plate.

3- Seal the basement

  • Use caulk and weatherstripping to seal gaps in windows and exterior doors. Caulk for stationary gaps, weatherstripping for friction surfaces.

4- Seal the foundation

  • Sill plates are wooden structural members anchored to the foundation, and the house is built on top of and anchored to it. Seal any cracks between the sill plate and the foundation.
  • Seal the interior part of any openings that go through the foundation for hose bibbs, electrical cables, HVAC lines, dryer vents, gas water heater vents, etc.
  • Seal cracks in the concrete or mortar joints with a mortar-specific caulk like 

5- Seal the attic

  • Use caulk and weatherstripping on doors and windows
  • Attic areas you can tackle yourself
    • holes in the attic floor or roof for lights, ceiling and vent fans, plumbing stacks, or attic access-use low-expansion spray foam insulation (usually marked for doors and windows).
  • insulation in the attic is a very important part of sealing up your house, but installing it usually calls for a pro.

So don’t let your house go into that long winter’s night without its coat buttoned. Seal up those gaps, save money, and stay warm! We’re always available to answer your questions about sealing your house, or anything else house-related. Reach us at 717-745-5545, or at chestnutinspections.com!

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