How to fit a door weather bar

Video: How to Fit a Stormguard and a Weather Bar to a Door. This walk-through is based on the video “How to Fit a Stormguard and a Weather Bar to a Door” on YouTube, which shows the process of fitting both a low-profile threshold and a rain deflector to an exterior door. Useful for understanding how the two components work together before you buy anything.

1. Understand the two components: weather bar and rain deflector

A door weather bar is a low aluminium or uPVC threshold strip that screws to the floor or door sill at the base of the door opening. It carries a flexible rubber or brush seal that presses against the bottom of the door when it is closed, blocking the gap. Some designs include a small ramp profile that also acts as a drainage channel for any water that does reach the threshold.

A rain deflector (or weather board) is a separate angled strip that fixes to the outside face of the door, just above the bottom edge. Its job is to throw rainwater away from the door rather than letting it run down and sit at the threshold. The two used together — deflector on the door, weather bar on the floor — give much better protection than either alone. Stormguard is probably the best-known brand in the UK for both products and you will find them in most builders’ merchants and online.

2. Measure up and choose the right product

Measure the width of the door opening at floor level — not the door itself, but the opening between the door stops. Most standard UK exterior doors are 838 mm (2’9”) or 914 mm (3’0”) wide, but measure yours rather than assuming. Weather bars and rain deflectors are usually sold in lengths that need cutting to size, so measure carefully and mark the cut line in pencil before touching a saw.

Also check the clearance under the door. With the door closed, measure the gap between the bottom of the door and the floor or existing threshold. The weather bar needs to fit within this gap with enough room left for the door to open and close freely without dragging. Most low-profile weather bars are under 15 mm high, which works for the majority of external doors, but it is worth checking. If there is a thick mat on the inside, move it before you measure.

3. Cut the weather bar and rain deflector to length

Mark the cut line clearly with a pencil and a square. Both strips are aluminium and cut cleanly with a hacksaw or a fine-tooth mitre saw. Clamp the bar down before cutting — it will shift around if you try to hold it by hand. After cutting, file or sand the cut end smooth so there are no sharp edges that could catch on the carpet or on bare feet.

Offer the cut bar up to the opening to check the fit before you drill anything. It should sit flush against both door stops with a small gap of no more than a millimetre or two at each end. If it is a fraction long, a couple more passes with a file will sort it. Do not try to force a too-long bar into position — it will bow in the middle and the seal will not seat properly.

4. Fit the rain deflector to the door

The rain deflector goes on the outside face of the door, usually positioned so its bottom edge sits about 6–10 mm above the bottom of the door. Hold it in position and mark the screw hole locations with a bradawl or a fine pencil. Drill pilot holes if the door is timber — hardwood doors in particular will split if you drive screws in without them. For a uPVC door, the screws supplied with the deflector should tap straight in without pre-drilling, but go carefully.

Most rain deflectors come with self-tapping screws and fixings. Fit from the centre outward to keep the bar straight. Check it is level before driving the outer screws home. A deflector that is slightly angled will throw water to one side rather than evenly away from the door bottom, which can cause pooling at one end of the threshold.

5. Fix the weather bar to the floor

Position the weather bar centrally in the door opening, pressing the seal up against the bottom of the closed door. Mark the fixing hole positions through the pre-drilled holes in the bar. Open the door and drill pilot holes or plug holes depending on whether you have a timber, concrete, or tiled floor. Screw the bar down firmly but not so tight that you distort the aluminium profile.

On a concrete or quarry tile floor — common in older East Kent properties — you will need a masonry drill bit and wall plugs. Take your time drilling; rushing on an old quarry tile will crack it. Some installers also run a thin bead of frame sealant under the weather bar before screwing it down, which stops water working under the base in driving rain. It is a good idea, particularly for a south- or west-facing door that takes the full force of a Channel squall.

6. Check the seal and adjust if needed

Close the door and look at the seal. It should be in light, even contact with the door bottom all the way across. If there is a gap at one end, check whether the weather bar is level — pack one end very slightly with a thin shim if the floor is not perfectly flat. If the seal is compressed too hard and making the door difficult to close, the bar may need to come up a fraction. Most weather bars allow a small amount of height adjustment by loosening the fixing screws and repositioning.

Open and close the door a dozen times to make sure it swings freely without catching on the seal. Then step outside on a rainy day and check the bottom of the door frame stays dry. If water is still getting under from the sides of the opening, that is a separate problem — usually worn door-stop seals or a gap in the door frame itself — and will need addressing independently.

When to call a handyman

Call Richard if the door has dropped on its hinges and the gap underneath is uneven, if the existing threshold is rotten or the floor is badly cracked, or if you need a full draught-proofing job across multiple doors and windows done in one go. Fitting a weather bar on a solid, level threshold is a quick job, but getting it right on an older or uneven door frame is where experience helps. Richard covers property maintenance and handyman repairs throughout Sandwich and East Kent.