I'm building a deck which is 7740mm x 2400mm outside the house. It will be freestanding (not touching) and I've made the base out of 200 x 50mm joists(all treated and Endseled where the cuts were made) sitting on 10 caithness stone pads(only 200mmsq each) bedded on concrete pads. It's effectively 4 bays 1935x2400mm.
2 bays have been made to this size but now I'm wondering whether to reduce the next bays by 9mm (1926mm) and put in some plastic 6mm spacers between the frames so that they are not hard bolted to each other, allowing ventilation. Or should I just keep to the same sizes and bolt them together, and cover any doubled up joists with some dpc/thin roofing felt prior to putting the deck on?
Where the joists sit also concerns me- I could put down felt but isn't there any form of spacer on the market that could be put below the joists to keep them off the pads enough to ventilate more effectively around them?
Would those plastic packers (1-6mm) joiners use to neaten up the second fix be strong enough to support the weight?
I've spaced the pads accurately enough so that I could overhang them with the frame just a few mm, as this would allow me to put the fascia deck boards down to almost ground level- which would look far better and prevent gravel disappearing under the deck over the years.
There seems to be a lot of development in composite boarding, hardwood boards etc but what's the point when everyone has to use good old bog standard softwood joists- these will always be the weakest link, so what if the deck itself will last a lifetime when the frame it's on will not....
Can anyone advise a bombproof way of maximising the life of the joists?
2 bays have been made to this size but now I'm wondering whether to reduce the next bays by 9mm (1926mm) and put in some plastic 6mm spacers between the frames so that they are not hard bolted to each other, allowing ventilation. Or should I just keep to the same sizes and bolt them together, and cover any doubled up joists with some dpc/thin roofing felt prior to putting the deck on?
Where the joists sit also concerns me- I could put down felt but isn't there any form of spacer on the market that could be put below the joists to keep them off the pads enough to ventilate more effectively around them?
Would those plastic packers (1-6mm) joiners use to neaten up the second fix be strong enough to support the weight?
I've spaced the pads accurately enough so that I could overhang them with the frame just a few mm, as this would allow me to put the fascia deck boards down to almost ground level- which would look far better and prevent gravel disappearing under the deck over the years.
There seems to be a lot of development in composite boarding, hardwood boards etc but what's the point when everyone has to use good old bog standard softwood joists- these will always be the weakest link, so what if the deck itself will last a lifetime when the frame it's on will not....
Can anyone advise a bombproof way of maximising the life of the joists?