Why Do Doors Swell in the Rain? Which Door and Board Don't Swell in the Monsoon

Short answer: wood and wood-based boards take up moisture from the air and expand a little. Doors swell most where the edges are left open, the grade is wrong for the place or the chaukhat sits in a damp wall. In bathrooms use a WPC door and frame; elsewhere seal all six faces and choose BWP where moisture reaches.

Why doors get tight in the rain

Wood and wood-based boards absorb moisture from the air and expand slightly, then shrink again in dry weather. Delhi's two to three monsoon months are very humid, so:

• the door sticks in the chaukhat,
• the lock's latch moves out of line,
• the bathroom door swells at the bottom,
• the laminate's edges lift.

It happens far more when the material doesn't suit the place.

The real causes are in the material

Cause	What happens
Open edges	No paint or laminate on the top and bottom edges: most moisture gets in here
The wrong grade	An MR-grade door in a bathroom or kitchen
Finish on one side	Laminate or paint on one side, the other bare: the door also bends
A damp chaukhat	Damp in the wall swells the frame, which squeezes the door
Floor water	Bathroom water creeps up the bottom edge

Which doors stay right in the damp?

Place	Door	Chaukhat
Bathroom or toilet	WPC door: doesn't absorb water	WPC chaukhat
Kitchen or balcony	BWP flush door or WPC	WPC or treated wood
Rooms on a ground floor or with a damp wall	BWP solid core flush door	Treated wood, bottom sealed
Rooms on an upper floor	MR solid core flush door	Wood or plywood

Chaukhat materials compared: which material for a chaukhat. The door material list: which plywood for a door.

Four things when fitting a new door

1. Seal all six faces: both faces, both side edges, and the top and bottom edges too (the ones you don't see).
2. The same finish on both sides: laminate on both, or paint on both.
3. A small gap at the bottom: enough between a bathroom door and the floor that mop water doesn't touch it.
4. The grade for the place: WPC or BWP for wet places.

An existing door swells every monsoon?

That points to the material: an MR door in a wet place, or open edges. If a door keeps swelling and the laminate keeps lifting, replacing it with a WPC door or a BWP flush door is cheaper in the long run.

FAQ

Does a WPC door swell in the rain? WPC doesn't absorb water, so moisture doesn't swell it. That's why it's best for bathrooms.

How waterproof is a BWP door? BWP glue holds even in water; with sealed edges it does well in damp places. For places that stay wet, WPC is better.

Nitin Plywood House, Alipur

We stock flush doors (MR and BWP), WPC doors, laminate, edge band and hardware. To check which size and brand is in stock today, call +91-9212017608. See flush and WPC doors.