mdf window boards

[andy21275]

hi all, just at the stage now to put window boards in my new conservatory. I am just asking for suggestions as to what timber to use. I could use pvc but i think it will look cheap and tacky, so i thought use mdf board but not sure if it will warp and bow due to moisture, sunlight etc... i have put in a 100mm cavity between walls and filled the cavity tops with the 25mm cavity closures to try and stop alot of moisture rising up. If I use mdf what is best to put on it to help it with the moisure, maybe gloss the bottom of the board aswell?

any comment will be much appreciated
cheers
andy

 

[ColJack]

if you use 20mm MDF painted, it's probably going to be a lot more stable than a real wood product..

push the boat out, get some granite ones made..

 

[andy21275]

cheers coljack, mdf it is then. should i screw into concrete blocks or just gripfill or both. i have used gripfill before when doing small bits of skirting and after a yr or two they are falling off due to movement in timber
cheers

 

[ColJack]

I'm a sparky so don't take my word for it, but any engineered product will be more stable than a natural one of the same sort..

paint all sides of it..

drill and screw might be a good idea, but a soft glue like mastic rather that gripfill which sets hard might be better for products prone to movement..

 

[noseall]

We use mdf regularly.

It is quite thick (25mm) so it does not distort or warp (cup).

TOP TIP

Once you have fitted the cav closers, add a little ex-foam to any gaps or run the silicone gun along the join.

Once set, dab some plasterboard to the top of the masonry and over the cav closers. This can be tapped very true and level. Let it set.

You now have a perfect surface onto which you can fix the window-boards using a cartridge adhesive.

 

[andy21275]

ok thanks, that is good advice, will get onto it on thursday morning. Be glad when it finished.
thanks again all