Are hardwood windows sills recommended?

[BeerBoy]

I am having a new conservatory fitted but the builder recommends laminated window sills rather than hardwood. This is due to hardwood ones twisting due to the heat and so will not be guarenteed.

I am very surprised by this as I see wood used everywhere (inside os a sauna for example).

Is this true what he says or is he trying to con me?

Thanks in advance

[geraldthehamster]

I'm not a timber expert, but this sounds like rubbish to me.

Cheers Richard

[The Natural Philosopher]

Its sort of true.

you do get pretty fierce humidity variation's in cills, and variations top to bottom as well which makes for easy warping. HOWEVER the answer is pretty simple: Screw then down hard to something, or if its a brick type base, use car body filler. I did this very successfully once. That cill never ever moved... nice bit of iroco blocks..

The warping is far worse with cheap softwood: that's why all cheap painted cills are now MDF. A far more stable alternative, But hardwood is usually pretty good. I've got 15mm oak here screwed down hard, and no issues at all.

[Chris George]

Dear BeerBoy I do have a bit of expertise on this Hardwood is a pointless term to use

Balsa is a hardwood so is oak , luan, and teak

In terms of durability only the HEARTwood of hardwood is durable Durability varies from under 5 years in ground contact for a 2" X 2" stake to over 25 years Perishable to very durable (BRE 245 that was)

Dimensional changes are yet another factor

What is the laminate made of?

Were it mine I would opt for a well treated Redwood sill with an OS (if I could find one) Vac vac treated timber or Teak, iroko or any grade 5 durability heartwood of hardwood

You could use a grade three such as English oak and treat it and paint it It would last but will move

If you let me know what specification is being provided for the laminated timber with respect to decay treatment and species I can advise chris

[Bolted]

What do you think of Accoya (TM)?