The Spongy Sill: Why Cheap Garden Room Doors Let the Rain In
Is the floor inside your garden room turning spongy after heavy rain? Discover why screwing frames into bare wood causes severe damp, and how proper flashing keeps the water out.
You drop five grand on massive aluminium bifold doors for the new garden studio. They look the business in summer. Then October hits. We get a proper coastal gale blowing in off the sea.
You walk out there the next morning, step inside, and the floor goes squish.
The laminate flooring is blown. It’s completely spongy right across the doorway. Customers ring me up swearing they have garden room leaking doors. The doors are fine. The bloke who fitted them is the problem.
Here is why your new floor is rotting, and the heavy engineering required to keep the water outside where it belongs.
The Bare Wood Trap
Installing doors in SIPs is not like fitting a kitchen cabinet.
You can't just push the heavy metal frame into the hole and drive massive screws straight into the raw timber. That is what cowboys do to save time. They skip the garden studio DPC (Damp Proof Course) entirely. They leave the structural wood completely exposed.
When the coastal rain hits that door, gravity takes over. The water runs down the glass, hits the metal sill, and tracks backwards. Water tracking under sill frames happens on every single cheap build. The moisture gets sucked straight into the raw timber.
The Mushy Floor
Once water gets under that sill, you are in serious trouble.
It creeps straight under the door track and hits your interior floorboards. You end up with severe damp under bifold doors. The water just sits there in the dark. Your expensive laminate flooring acts like a giant sponge. It sucks the water up, swells to double its thickness, and peels apart at the seams.
The whole entrance turns to mush. You can't just dry it out with a blow heater. You have to rip the entire floor up, dry the subfloor out, and pay for the whole lot to be laid again.
Wrapping the Frame
We do not leave bare wood. Ever.
Before the bifold doors even arrive on site, we prep the opening. We wrap the entire structural timber frame in heavy-duty waterproof membrane. We overlap every joint and tape it completely flat. Then, we sit the heavy aluminium frame on top of a proper physical DPC.
Once the door is bolted in, we seal the outside edges with exterior flashing tape. The water is physically blocked. The rain hits the sill and drops straight down onto the patio. It never touches the timber. It never gets anywhere near your flooring.
Stop letting cheap builders ruin your property.
Pop down and see the lads at 78 Alma Rd, Bournemouth BH9 1AN, UK, or ring the site phone on 07835 390845. We’ll show you exactly how we wrap a structural opening.
