Storm-Proof Casement Windows
Lipped Accoya casements designed for exposed moorland, coastal and hilltop properties — the sash sits proud of the frame, giving you a stepped weather barrier that shrugs off wind-driven rain. Handcrafted, factory-sprayed, guaranteed 30 years.
The Design
A storm-proof casement — sometimes called a lipped casement — is an outward-opening timber window where the opening sash closes proud of the outer frame, overlapping it by around 12–15mm on all four sides. Look at one from the outside and you'll see a visible step and shadow line where sash meets frame; look at a flush casement and the two sit level, forming a single flat plane.
That lip is the whole point. When wind drives rain sideways against the elevation — the reality on any exposed North Yorkshire hilltop, Dales farmhouse or coastal cottage — the water has to negotiate a physical step before it can reach the weather seal. Rain runs off the lip and back down the frame instead of being forced into the seal line by pressure.
It's a design that emerged in the 1950s specifically to solve the weather-tightness problems of old timber flush casements. Modern flush casements have caught up in seal technology, but the storm-proof profile still gives you an extra margin on the harshest elevations — and remains the most popular residential window profile in the UK.
The Fit
The lipped profile earns its extra margin on sites where the weather does its worst work:
If your property is sheltered — surrounded by trees, in a valley, or in a terraced street with buildings on all sides — a flush casement will perform just as well and look quieter. Storm-proof is a considered choice, not a default.
Flush vs Storm-Proof
Both are casement windows. Both can be Accoya, both can be factory-sprayed dual-colour, both come with a 30-year guarantee. The only real difference is the sash-to-frame junction — here's what that means in practice.
Not sure which one is right for your property? Send us a photo and postcode — we'll tell you honestly, based on the elevation and exposure. No pressure either way.
Specification
Every storm-proof casement we make is built to the same handcrafted spec as our flush casements — the only thing that changes is the sash profile.
Why Bailey Hague
We've fitted storm-proof windows into moorland farmhouses on the North York Moors, coastal cottages on the Yorkshire Wolds, and hilltop conversions in the Dales. When the weather has a proper go at your elevation, the joinery has to be right first time — because you're not going to want to be up a ladder in November recaulking anything.
Send us a photo of the elevation and a postcode. We'll come back within one working day with an honest steer on whether storm-proof or flush is the right call for your property, and a rough budget indication before we book a survey.
Request a free quoteFAQ
A storm-proof casement (also called a lipped casement) is an outward-opening timber window where the opening sash sits proud of the outer frame when closed, overlapping it by around 12–15mm on all four sides. That lip creates a stepped, physical barrier against wind-driven rain and draughts, so the design performs particularly well on exposed sites like the North York Moors, the Yorkshire Dales, and coastal properties.
A flush casement sits level with the outer frame when closed — the sash and frame form one flat exterior plane, which reads as more traditional and elegant. A storm-proof casement has a sash that overlaps the frame, giving a visible step and shadow line on the outside. Both are casement windows; both can be Accoya, both can be spray-finished. The difference is the sash-to-frame junction — flush is quieter visually, storm-proof gives you extra weather margin on exposed elevations.
Exposed, high-rainfall or high-wind sites — moorland properties, coastal homes, hilltop houses, unsheltered north-facing elevations, and new builds in categorised exposure zones (BS EN 12208 exposure category 4+). They're also a common specification for post-war and 1960s–90s properties where storm-proof was originally installed and the homeowner wants to keep the same look.
In modern timber windows, both perform very well — with today's compression seals and 24mm double-glazed units, a well-made flush casement matches a storm-proof on air permeability and water tightness under BS EN 12208 testing. Storm-proof has a small edge in the most severe wind-driven rain (category 6+ exposure) purely because of the physical rebate. For most Yorkshire installations, energy performance is dictated by the glazing spec, not the sash-to-frame junction.
Yes — all our storm-proof casements are made in Accoya as standard, with a 30-year above-ground guarantee against rot and warping. Accoya is particularly well-suited to storm-proof designs because the rebated sash junction faces the harshest weather exposure of any window detail, and Accoya's dimensional stability keeps the seal line true year-round.
Our Accoya storm-proof casements carry a 30-year guarantee against rot and warping and are expected to last well over 60 years. Traditional hardwood storm-proof windows typically last 40-60 years when properly maintained. Repaint every 8-10 years to keep the paint film in peak condition.
Yes — we regularly do like-for-like storm-proof replacements on 1960s–90s properties. We'll match the sash lip dimensions, the sight lines, the mullion positions, the astragal bar pattern and the colour. From the outside, the new windows read the same as the ones they replaced, just with a modern glazing spec and a 30-year guarantee underneath.
Typical lead time from order to installation is 8-12 weeks depending on complexity and time of year. Urgent projects and single windows can often be turned around faster — please ask when you enquire.