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INSULATION IDENTIFICATION GUIDE
INSULATION INSPECTION & IMPROVEMENT
ACOUSTICAL SEALANT CHOICES
AIR LEAK DETECTION TOOLS
AIR LEAK MINIMIZATION
AIR LEAK SEALING PROCEDURE
AIR SEALING STRATEGIES
ATTIC LEAKS, CONDENSATION & MOLD
BASEMENT CEILING VAPOR BARRIER
BASEMENT HEAT LOSS
BLOWER DOORS & AIR INFILTRATION
BRICK LINED WALLS
BRICK VENEER WALL AIR LEAKS
BUCKLED FOUNDATIONS due to INSULATION?
CATHEDRAL CEILING INSULATION
CATHEDRAL CEILING VENTILATION
CONDENSATION or SWEATING PIPES, TANKS
COOLING LOAD REDUCTION by ROOF VENTS
DEW POINT CALCULATION for WALLS
FRAMING DETAILS for BETTER INSULATION
FRAMING DETAILS for DOUBLE WALL HOUSES
FRAMING METAL STUD PERFORMANCE
FREEZE-PROOF A BUILDING
FROST HEAVES, FOUNDATION, SLAB
GREENHOUSE DESIGN for SOLAR HEATING
HEAT LOSS in BUILDINGS
HOT ROOF DESIGNS: Un-Vented Roof Solutions
HOUSEWRAP AIR & VAPOR BARRIERS
HUMIDITY LEVEL TARGET
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INSULATION INSPECTION & IMPROVEMENT
INSULATION R-Values & Properties
LEED GREEN BUILDING CERTIFICATION
MOISTURE CONTROL in BUILDINGS
NOISE / SOUND DIAGNOSIS & CURE
ODORS & SMELLS DIAGNOSIS & CURE
SOUND CONTROL in buildings
STAIN DIAGNOSIS on BUILDING INTERIORS
THERMAL MASS in buildings
THERMAL TRACKING & HEAT LOSS
VAPOR BARRIERS & CONDENSATION in buildings
VENTILATION in BUILDINGS
WALL CONSTRUCTION BARRIER vs CAVITY
WIND WASHING INSULATION At EAVES
WINDOWS & DOORS
WINTERIZE A BUILDING
WOOD, COAL STOVES & FIREPLACES
WOOD STOVE SAFETY
This article describes step by step procedures for sealing air leaks and gaps around building windows and doors, working from indoors to save energy costs and stop air leaks. Our page top photograph demonstrates a common point of air leakage around windows on a New York home constructed in the 1960's. Taking advantage of a project to install new interior window trim, we found, insulated, and sealed these 1/4" to 1/2" air gaps around the building's windows and doors. Here is how we did it.
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Readers should see AIR LEAK MINIMIZATION and also AIR BYPASS LEAKS, and be sure to read ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE. See BLOWER DOORS & AIR INFILTRATION and see HEAT LOSS DETECTION TOOLS for more sophisticated and accurate methods of detecting points of un-wanted building heat loss or heat gain. At THERMAL TRACKING & HEAT LOSSwe describe other visual clues that can help spot points of significant air (and heat) leakage in buildings. Also see PASCAL CALCULATIONS where we describe air infiltration rate rules of thumb.
Working from Indoors to Provide Air Sealing at Leaky Windows Can Cut Heating Bills
We took advantage of the plan to replace 1960's vintage painted clamshell interior window and door trim with new custom cut wood trim to also expose and seal gaps around the windows and doors of a Poughkeepsie New York home. Here we provide a step by step photographic guide to how we pulled trim, found gaps, and sealed them before installing new window trim. We include extra details on trimming back drywall at floor level to reduce the chances of future mold growth behind floor trim baseboards.
At left our photo shows an example of the original common pine clamshell window trim that was installed when this home was built for a Vassar College professor in the 1960's.
On a cold windy winter day, at leaky windows it is sometimes possible to actually feel cold air movement at building windows and doors. But more often, warm air is leaking out at some openings just as cold air is leaking in at others. So relying on your open hand to feel for and detect window air leaks is less obvious than using more sophisticated HEAT LOSS DETECTION TOOLS.
At ENERGY SAVINGS RETROFIT CASE STUDY we include the air sealing results for an older, costly-to-heat home for which simply adding insulation didn't do the trick.
But here we provide an example of an easy, low-cost, low tech energy savings step that is likely to benefit many older homes.
The sequence of steps in this building air leak sealing project was simple and can be accomplished by most homeowners with only basic handyman skills and simple tools.
Step 1 in Window & Door Air Leak Seal-Up - Remove the Old Trim Boards
Our photos below show the basic tools you'll need to remove window or door interior trim (below left) and how we use a putty knife and mini pry bar together to remove window trim without damaging it (below right).
From left to right you can see:
The window glazing (and a view outdoors), parting strips that are holding the window glazing in place (painted brown)
The window jamb frame itself - this is the frame into which the window glass was set.
A gap between the window jam and surrounding drywall.
[Not visible] the 2x lumber framing the window rough opening is behind the drywall and behind the piece of trim we're holding up.
The wall side (previously hidden) of the clamshell window trim with a rusty finishing nail protruding at the top of the trim piece.
Watch out: don't drop boards with nails on the floor where you'll step on a nail! And if working overhead, wear eye protection so you don't drop debris into your eyes.
Step 2 in Window & Door Air Leak Sealing - Find the Air Gaps, Clean Out Debris
Find the gaps between the window or door jamb and the drywall or other wall covering. Large gaps, 3/16" to 1/4" or more will be filled with fiberglass insulation. Smaller gaps will be sealed with a sealant-caulk. Our second photo, below right, shows the beginning of caulking.
Remove loose joint compound over gaps: In most cases it's easy to use a putty knife or the small pry bar to remove the joint compound that partly closes off some of these gaps, giving plenty of room to then insert our insulating material (photo below left)
Inspect for existing insulation: Looking into the gap between jamb and framing, you will sometimes see a bit of insulation that was installed by someone working on the window or door trim from outside (photo below right) - this procedure can be accomplished from either indoors or outside.
Step 3 In Air Leak Sealing at Windows & Doors - Insulate & Seal Gaps
Large window or door gaps are sealed with fiberglass as we demonstrate above, or you can also seal these gaps with with expanding foam insulation from a spray can. Using fiberglass, gently push fiberglass strips into the exposed gaps between the window or door jamb and the rough opening. (Photos above). Using expanding spray foam provides a superb seal against air leaks, but adds time to the job as you need to wait for the foam to expand and harden, then you'll need to cut off any excess protruding from the wall before you can proceed.
If we're going to use fiberglass to fill large gaps around windows and doors we like to use pre-cut strips of fiberglass pipe wrap - this minimizes the ripping, cutting, and dust from chopping up fiberglass building insulation batts. Wear a dust mask, gloves, eye protection when working with fiberglass.
Our photo at below left shows how we insert fiberglass insulation into the gaps between window jamb and rough opening framing.
Watch out: a famous mistake made by enthusiastic amateur building air leak doctors is to pound or push too much insulation into the gaps around windows or doors. If you overdo it you will find that later you can't open or can't re-close your windows because you've bulged the window jamb. Also, over-packed fiberglass insulation may lose some of its R-value.
Small window or door gaps are sealed with a sealant/caulk as we show in the photographs below.
Watch out: Don't mistake joint compound for insulation at window and door gaps: often you'll find joint compound partly closing off a large gap between the window jamb and nearby framing. That's because the installer simply shimmed the jamb to the framed rough opening where the jamb was being nailed. The rest of the space around the window jamb was simply left open. (In current construction practices good buildings seal this space with fiberglass insulation or with expanding foam insulation to make an airtight window or door installation.)
Clean off excess sealant or caulk at the jamb/wall surfaces to leave a smooth surfaces. Otherwise protruding sealant may interfere with a neat trim installation by holding it off of the wall surface.
Watch out: don't rush. Seal thoroughly, and then be sure your sealant has dried enough that it won't glue the new window trim in place. Otherwise, if you need to remove the trim again in the future, say to replace a fixed glass window at an opening, you may have to ruin your trim in the course of its removal.
Tip: Extra Step to Reduce Future Water & Mold Damage to Drywall
Step 4 in Building Air Leak Seal-Up: Install new Window or Door Interior Trim
If you are re-using your old window trim, which saves time in cutting and fitting pieces, you'll have to have taken extra care not to damage the trim when you removed it. In our project the original intent was to install new, more attractive window and door trim, cut to fit.
Just as the open and leaky gaps around the building's windows had been hidden behind the old painted clamshell interior trim, the now-weather-tight seal around the same openings is hidden beneath the new trim.
By air testing, temperature, or thermography would it be easy to know that these window openings have been sealed. But the occupants could tell the difference on the first cold windy winter day, when they no longer felt drafts around the windows.
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