03 / GARAGE
Sealing the sides and top of a garage door
Everyone replaces the bottom seal. Almost nobody does the jambs and the header, which together are usually a bigger hole and cost less to close.
Side and top seals are flexible vinyl or rubber trim strips nailed to the jambs and header so the flange presses against the closed door face. Measure the two jambs plus the header, add a foot, and buy that length. Set the flange so it touches under light pressure — too much and the door binds.
Stand inside a closed garage on a bright day and look up the side jambs. On most houses there is a visible line of light down at least one of them, and often across the top. Added up, that is frequently more open area than the bottom of the door, and unlike the bottom it costs about twenty dollars to fix.
Work out the length you need
- 1Measure the height of one jamb from the floor to the header.
- 2Double it — you have two sides.
- 3Add the width of the opening for the header run.
- 4Add a foot for cutting and corners.
- 5A typical 7 ft high, 16 ft wide double door works out at about 31 ft. A single 7 x 9 ft door is about 24 ft.
Fitting: the flange pressure is the whole job
- 1Close the door. Everything is fitted against the closed door, not the open one.
- 2Hold the trim seal against the jamb so the flexible flange just touches the door face — enough to make contact along its length, not enough to bow.
- 3Nail the top first with a galvanized nail, then work down, checking contact every couple of feet.
- 4Do the header last, overlapping the tops of the two side pieces so water runs outward.
- 5Open and close the door twice. If it binds or the flange folds under, back the seal off a quarter inch and re-nail.
Common mistakes
- Fitting against an open door. The seal ends up nowhere near the door face when it is shut.
- Too much flange pressure. The door binds, the opener strains, and the flange creases permanently within a month.
- Butting the header piece between the sides rather than overlapping over them, so water runs into the joint instead of over it.
- Using vinyl in a severe climate. It stiffens and can crack at the nail line. The rubber version costs a little more.
- Ignoring the jamb itself. If the wooden jamb is rotten, no seal nailed to it will hold. Fix the wood first.
While you are in there
The garage is usually a house's biggest uncontrolled space, and the door is only part of it. Two other checks worth five minutes each: the person door out to the yard, which takes an ordinary door sweep, and the door from the garage into the house, which is often the leakiest interior door in the building — that one has its own page at drafty door to the garage.
Quick picks
Ranked for fit, not for hype. Tap a row to jump to the full write-up, or go straight to the listing.
| # | Product | Best for | Gap range | Price |
|---|---|---|---|---|
| 1 | M-D Garage Door Top and Sides Seal, 30 ft x 1-1/2 inThirty feet of vinyl trim seal — enough for the top and both sides of a double door in one purchase. | Doing the whole opening | Published 1-1/2 in flexible vinyl flange; overlaps the door face to close the jamb gap | CHECK PRICE |
| 2 | Garage Door Weather Stripping Top and Sides, 32.8 ft, with NailsRubber rather than vinyl for the top and sides, in a 32.8 ft roll with the nails actually included. | Rubber instead of vinyl | 32.8 ft trim seal; flange pressure set at install | CHECK PRICE |
| 3 | M-D Building Products 03822 Garage Door Seal Kit, 7 ftA 7 ft length for the single run that has failed, rather than redoing the whole opening. | One side or one header | 7 ft of vinyl trim seal for the top or one side | CHECK PRICE |
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Doing the whole opening
M-D Garage Door Top and Sides Seal, 30 ft x 1-1/2 in
Published gap range
Published 1-1/2 in flexible vinyl flange; overlaps the door face to close the jamb gap
#ad · how we are funded · no live price right now
Thirty feet of vinyl trim seal — enough for the top and both sides of a double door in one purchase.
Where the number comes fromM-D publishes the length (30 ft) and the width (1-1/2 in) and states nails are not included. A trim seal does not have a gap range: you nail it so the flange presses against the closed door, which is why install position matters more than the section here.
- Published length
- 30 ft
- Published width
- 1-1/2 in
- Material
- Flexible vinyl
- Fixings
- Nails NOT included
- Cut
- To length
- Mounting
- Nailed to the jamb (nails not included)
What it does well
- One roll does the top and both sides of a double door
- Vinyl flange conforms to a jamb that is not perfectly straight
- Cut-to-length install with a utility knife
Where it fails
- Nails are not in the box — buy galvanized ones at the same time
- Vinyl stiffens in deep cold and can crack if you slam the door
- Get the flange pressure wrong and the door will not close
Who this is forA garage where you can see daylight down the sides as well as under the door.
Rubber instead of vinyl
Garage Door Weather Stripping Top and Sides, 32.8 ft, with Nails
Published gap range
32.8 ft trim seal; flange pressure set at install
#ad · how we are funded · no live price right now
Rubber rather than vinyl for the top and sides, in a 32.8 ft roll with the nails actually included.
Where the number comes fromThe listing publishes the length (32.8 ft), rubber construction and included nails. Like every trim seal, it has no gap range — the flange has to touch the closed door.
- Published length
- 32.8 ft
- Material
- Rubber
- Fixings
- Nails included
- Use
- Top and sides
- Color
- Black
- Mounting
- Nailed to the jamb (nails included)
What it does well
- Rubber stays pliable in cold where vinyl goes brittle
- Nails in the box
- Enough length for a double door with spare
Where it fails
- Black is a strong line against a white jamb
- No named manufacturer behind the spec sheet
- Rubber flange is stiffer to compress than vinyl on a light door
Who this is forA cold-climate garage where vinyl trim seals have cracked before.
One side or one header
M-D Building Products 03822 Garage Door Seal Kit, 7 ft
Published gap range
7 ft of vinyl trim seal for the top or one side
#ad · how we are funded · no live price right now
A 7 ft length for the single run that has failed, rather than redoing the whole opening.
Where the number comes fromM-D publishes the 7 ft length and the tough vinyl construction, and states it withstands exposure to extreme temperatures. Install position sets the seal, not a gap figure.
- Published length
- 7 ft
- Material
- Tough vinyl
- Use
- Top and sides
- Claim
- Withstands extreme temperatures
- Model
- 03822
- Mounting
- Nailed to the jamb
What it does well
- Right size for replacing one damaged run
- Cheap enough to keep a spare length
- Same material as the 30 ft roll
Where it fails
- Three runs means three packs for a full opening
- White yellows in strong sun
- Nails still separate
Who this is forOne side of a garage door that got clipped by a car mirror.
How we picked
- Length requirements are calculated from the actual opening, not from a kit's marketing.
- Products placed by published length and material, with the cold-climate caveat stated.
We have not tested these products and we do not claim to have. The full method, including what we refuse to claim, is on how we pick.
Questions people actually ask
- How do I seal the top and sides of a garage door?
- Nail a flexible vinyl or rubber trim seal to the jambs and header with the flange pressing lightly against the closed door face. Fit with the door closed, start at the top of each side, and overlap the header piece over the side pieces so water sheds outward.
- How much side seal do I need for a garage door?
- Twice the jamb height plus the opening width, plus about a foot for cutting. A 7 ft by 16 ft double door needs around 31 ft; a 7 ft by 9 ft single needs about 24 ft.
- Should the garage door seal touch the door?
- Yes, lightly. The flange should make contact along its whole length without bowing. Too much pressure makes the door bind and creases the flange permanently.
- Do garage door side seals come with nails?
- Often not — several published listings state nails are not included. Buy galvanized or stainless nails at the same time, since these strips live on an exterior jamb that gets wet.
Sources
- M-D Building Products — published 30 ft x 1-1/2 in vinyl top and sides seal, nails not included
- M-D Building Products — vinyl garage door top and sides seal product page
Every specification on this page traces to a published manufacturer or retailer listing. Where a maker publishes no working gap range, we say so rather than estimating one.
Read next
The best garage door bottom seals
Rubber and EPDM seals by published length and fixing type, plus the case where a bottom seal is the wrong buy.
Rubber, vinyl or brush: garage door seal materials
Three materials, three positions on the door. Getting them the wrong way round makes things worse.
The drafty door between the house and the garage
Thermally an exterior door, treated like an interior one. Seal it properly — and keep the closer working.