[quote="Milnathort"]Joiner using cladding on outside of porch being built. cladding has stamp on it saying not to be used externally,does this matter or should i tell him.[/quote]
If you want a timber which will give virtually unlimited life span with little or no maintenance then go the extra mile and buy cedar cladding. Although quite soft it should last forever and if you treat it with cuprinol it will hold the colour longer than pine.
Second best on the readily available timbers is red pine which will need treating more frequently.
Equal second best is UPVC which goes brittle, matt and discolours.
Bottom is white pine normally used indoors for framing.
Materials should be suitable for the purpose for which they are intended.
The manufacturer does not recommend this cladding for external use so if it cracks or if knots fall out you cannot take it back to the supplier.
Sounds like your joiner has slipped up. Nip it in the bud and reject the work immediately or before it is fixed while you have the proof even if it means making a photocopy of the manufacturer`s recommendations for use.
Thank you friend for informing me that the joiner i had employed to build my porch was using the wrong type of cladding. I pointed this out to him and he admitted to his mistake and replaced the internal cladding with good quality external cladding.