Thread: Timber species best suited for verandahs

Originally Posted by JB

So the outside nail moves up to 10mm?!

A chippy explained it to me in the following terms once. If you lay 100 mm boards 10 across, allow for 1% expansion/ contraction due to humidity etc. Doing the maths implies that boards have the potential to go from 100mm in dry stable conditions, to 101 in humid conditions. Mutliply that by 10 and theoretically, yes you may get up to 10mm of movement across 10 boards.
I am not a chippy but have always applied those principles to the floors I have laid. Understand that a skirting board typically covers the gap you leave as well as plaster being hung just above the floor.
I recently cut out and replaced 2 boards for a friend of mine who had unfortunately suffered some flooding in his family room that caused 2 boards to pyramid and split due to no expansion gap being left on the outer edges of floors installed by a so called professional.
Anyone else help out with JB's query?

Originally Posted by hatemondays

If you lay 100 mm boards 10 across, allow for 1% expansion/ contraction due to humidity etc. Doing the maths implies that boards have the potential to go from 100mm in dry stable conditions, to 101 in humid conditions. Mutliply that by 10 and theoretically, yes you may get up to 10mm of movement across 10 boards.

I agree, or more.

It's the nailing that confuses me. A nailed board is not going to move 10mm to the left or right.

Originally Posted by JB

I agree, or more.

It's the nailing that confuses me. A nailed board is not going to move 10mm to the left or right.

i have never actual thought about it but i have seen entire floors "grow" by 20 and 30mm so they must move, bearing in mind floors are mostly fixed with staples these days

Originally Posted by Gaza

...... floors are mostly fixed with staples these days

That's my other dilemna. I have always secret stapled my internal floors and proposed to do the same for the verandah deck because I love seeing no nail holes or putty marks. The few people I have spoken to about that have all been very blunt about not doing so. I can understand that from the perspective of the timber being outside and thus subjected to more extreme fluctuations in humidity than a relatively stable internal environment, so I've decided to topnail the boards with twist nails. Overkill?