Step into any home or commercial space and you’ll likely come across weather seals.

These unsung heroes of joinery look good, framing external doors and windows, but they also play a pivotal role in energy efficiency.

In this guide we look at weather seals in detail, including what they are, how they work and why they’re an essential part of every seasoned joiner’s kit.

What is weather seal?

A weather seal is key to your door and window set-up. It fills gaps by creating a tight seal between the door or window and its frame. This prevents air leakage and water ingress which can damage the structure of the door or window and its finish.

Weather seal acts as a barrier between interior and exterior environments, helping to maintain comfort, reduce energy costs and protect against weather-related damage.

Blocking unwanted gaps by draught-proofing could save around £35 a year in Great Britain and is simple to do.

How does compression seal work?

In a door or window, weather seal fits around the frame, closing the gap and creating a tight seal for weather resistance and insulation.

The most effective weather seals are made from materials such as rubber, foam or plastic, which offer flexibility and durability.

Coastal Group is a main distributor of Deventer weather seal, made from high quality TPE closed-cell microfoam which is resistant to water absorption, helping to prevent timber rot.

Parts of a door

In a door, the seal goes around the perimeter of the jambs (as shown above). Attach it to the door’s side jamb and to the door stop across the head.

It can also be placed in the meeting stile on a set of double doors.

This ensures that when the door is closed, a tight seal is formed around the frame, preventing air leaks.

Choosing the right seal

Coastal specialises in four types of weather seal:

1. Compression – most commonly used

2. Wiping – provides extra insulation around windows and as a sweep on the bottom rail of a door

3. Glazing gasket – often used to seal around the glass on the outside of an opening door or window

4. Sliding sash – effective when used between the upper and lower sash and on the bottom rail of traditional sliding sash windows

Let's look at each in more detail...

1. Compression weather seal:

Coastal recommends Deventer compression weather seal SPV124, which is available in sizes 12mm, 15mm and 18mm, depending on the size of the rebate, for various door and window applications.

2. Wiping seal:

This is a type of weather stripping, used where the door or window sash brush against a surface. They are commonly attached to the bottom rail of a door sealing tightly against the threshold, or around the frame in a casement window.

3. Glazing gasket:

In a window, run the gasket around the perimeter of the exterior flush casement.

Coastal Group offers the SV2 and the SV7 glazing gaskets available to buy online or by phone/email.

The SV7 is more slimline than the SV2.

4. Sliding sash:

If you’re working with a traditional sliding sash window, insert flipper seal (SP5920) along the top rails, the meeting rails and the bottom rails for a secure fit.

The range of weather seals and gaskets can seem overwhelming. Get the confidence you need for your next project by talking it through with our team of experts.

Coastal’s customer service team can advise on which seal is most relevant, how to use it, and what others you may need. Get in touch by calling 01726 871 025 or drop us an email.

Request your weather seal sample pack, containing 18cm lengths of SPV124-15, SP5920, SP63, SP5717 and SV7 by clicking the link below.

Click here to request your free weather seal sample pack