Panel expansion gap

[paisawood]

I am currently making a pair of external oak shutters for someone's cottage in France and would welcome some advice on the allowance I should make for expansion and contraction of the inset panels. The shutters will be exposed to hot sun in the summer and driving rain in winter.

Each shutter is 1800mm high by 600mm wide and comprises of a conventional rail and style frame with through m&t joints and three inset raised panels. The panels are each approximately 470 mm square and 14mm thick and will be set into 10mm deep grooves in the frame.

As the shutters will be exposed to a wide range of temperatures and humidities, I am thinking of leaving a 4mm expansion gap on each side of the panels and 2 mm at the top and bottom but am not sure if this will be too much or too little. (The timber is air dried english oak which was stored in the workshop for a month before machining.)

Also, what finish would you suggest? The customer wants to use boiled linseed oil but I'm not sure that this would be adequate.

Any advice would be appreciated.

Thanks

David

 

[Anonymous]

Sounds OK to me, I usually leave between 3 and 5mm gaps for expansion

 

[tim]

I'd be interested in the answers here too.

In the same vein, Someone has asked me to make an oak front door which faces similar conditions in that it faces driving rain in the winter (and summer by all accounts) but it opens into a small sitting room which is heated (to hotter than hell) with a woodburner in the winter.

Whats the best way of keeping the panels watertight and yet leaving the expansion gap functional?

Cheers

Tim

 

[Argee]

Whats the best way of keeping the panels watertight and yet leaving the expansion gap functional?

Cheers

Tim

What I've done in a similar situation (oak half-glazed doors with raised panels) is to get a reel of round rubber (like was used underneath some kitchen sinks to seal them to the worktop) and whang that in the groove first. If there is any expansion, the rubber should compress sufficiently, whilst allowing for a bit of shrinkage too.

Across the pond they sell tiny rubber balls or pellets to perform the same function, although I've not seen any myself.

Ray.