MR MDF door panel

Doug71 · 2 May 2018

I am making 2 external doors for a customer, they are both quite large, about 3'6" wide x 7' high, 57mm thick (I like to mix the imperial and metric)

The style is a tongue & groove kind of look similar to in the link below except one will have a small glass pane in, they will both be painted.

http://www.building-supplies-online.co. ... wsQAvD_BwE

The stiles and rails will be Accoya but instead of T&G boarding I am thinking of using a sheet of 15mm Tricoya MDF and grooving it to get the look. Internally a sheet of 15mm MR MDF again grooved with some 25mm kingspan sandwiched in the middle.

They are quite exposed and south facing so was hoping with the above spec they shouldn't move much.

Question is do you think MR MDF should be okay for the internal panel, they open in so it shouldn't see any weather.

Thanks in advance, Doug

HOJ · 2 May 2018

Only time will tell, but I made a window in principal, as you are describing, twin opening sash with one being boarded in, used Accoya for the frame and Tricoya for the panels , inside and out, primed and painted before putting together, not sure I would take a chance with MR MDF just in case you get interstitial moisture in the sandwich.

doctor Bob · 2 May 2018

Why not use external MDF to be fail safe?

owen · 3 May 2018

Or some WBP ply?

owen · 3 May 2018

Ah, just realised you want it grooved. Surely if you're buying a sheet of tricoya and pricing it into the job you'll have enough for inside and outside?

Doug71 · 3 May 2018

Thanks for the replies,

HOJ, yes it was interstitial condensation I was worried about, a problem that didn't seem to exist till a few years ago! Didn't know if I was better gluing the insulation to the panels so there was no gap or leaving a small gap? Also didn't know if some type of loose fill, fiberglass or multi foil insulation would be better?

Dr Bob, I will probably end up using external MDF, I have never used it before, always used MR internally and jumped up to Tricoya externally.

Owen, because the doors are large it looks like I will only get one panel from each sheet.