floating deck

[pistonmember]

Im making a deck today, its essentially a floating deck on a few patio slabs, it will be right up against the house but not fixed to it incase i ever need to move, could this cause a problem with sort of damp issues? It will only be raised to just below the lip of the patio door (3-4 inches off the ground)

[bigee]

Will be fine so long as you leave a nominal air gap next to the house,and I presume you will not be fixing a wall plate to it, as in it will be 'floating' ? You can always 'anchor' the structure down using short posts set into the ground a bit further back from the house that the main joists/frame can fix to.

[pistonmember]

bigee said:

Will be fine so long as you leave a nominal air gap next to the house,and I presume you will not be fixing a wall plate to it, as in it will be 'floating' ? You can always 'anchor' the structure down using short posts set into the ground a bit further back from the house that the main joists/frame can fix to.

How nominal are we talking? Basically im making a deck which is going to rest on patio slabs and not bolted to the brick but i want it close up against the house.

[Spudler]

Just fix some batten (vertical) spacers to timber adjacent to house & butt up to house.
You could always fix through mortar joints if you decide fixings are required.

[R6VED]

I am planning the same job and noticed that B&Q do some concrete mount type things for a £5 each so that you can lift the decking off the ground creating a moisture barrier.

You put a board in to the slot sideways and create a framework to mount the decking boards to.

Good luck and I look forward to seeing some pics of the finished article for inspiration.

[bigee]

Just leave a 10-20mm gap. Some will say you can get splashback etc higher than the damp but in the real world it will be fine(you would get the wall wetter when filling & spilling a watering can from an outdoor tap ! )

[herewego]

Why is it acceptable to ignore the rule that the DPC has to be 150mm above ground level? As I understand it the reason for this requirement is that rain will not bounce more than 150mm. Rain will bounce from decking just the same as from any other hard surface.

[ally_f]

Agreed, our decking was next to, but not touching or attached to, a neighbour's garage and it created him a real damp problem (mould up the inside walls the works). We fixed it by trimming the planks to around 4cm away from the wall to prevent run off / splash onto his wall.

[Spudler]

herewego said:

Why is it acceptable to ignore the rule that the DPC has to be 150mm above ground level?

Decking is different to soil or concrete etc, it allows an air flow.
With disabled access requirements it's common to have paths coming upto DPCs, so long as it all slopes away from the buildings there's no problem.

Single skinned garages will always be a problem.

[JackReacher]

I have also had some damp issues, which I think are caused by decking. Previous owner installed it, but there is at most a 5mm gap between it and the house, at the same level as the DPC. I'd like to remove it and replace it with a patio at ground level eventually but in the meantime I plan to trim it back by a couple of cm. I'm also not convinced the air bricks are getting sufficent air flow with it there.

[bigee]

Rain will bounce, splashback, hit the wall directly dependant on direction,wind , etc, regardless. If the deck does not touch the wall,is not attached to the wall, is 'raised' (on its joists ) so as air is circulating under same then it will be fine.
I have built a 'few'.

[pistonmember]

bigee said:

Rain will bounce, splashback, hit the wall directly dependant on direction,wind , etc, regardless. If the deck does not touch the wall,is not attached to the wall, is 'raised' (on its joists ) so as air is circulating under same then it will be fine.
I have built a 'few'.

So a deckboard is touching the wall, and the ends of 5 joists are touching the wall, but the patio slabs are spaced apart so theres some air flow going on, so could i still run into damp issues? The deckboard sits just nelow the dpc by about an inch.

[pistonmember]

??

[pistonmember]

Also ive noticed that the deck has a slight angle towards the right which i want to change so its 100% level, any ideas how to do this easily?? Theres no end to it so i can see the joist ends at the moment, the only thing im worried about is if i lift it slightly at one edge the joists might lose contact with the slabs??

[Spudler]

pistonmember said:

i want to change so its 100% level,

Should have a slight run away from the house.

[pistonmember]

Spudler said:

Should have a slight run away from the house.

Yeh it has but also leans to the left slightly which i hate