Expansion gaps on a sunken deck (walls on all side)

[Jamini]

I'm planning a deck on my patio which will be attached to the house with a ledger board and 10mm spacers. However, the patio is surrounded on all 3 other sides by a retaining wall and I'm worried if I attach the deck to the wall, when it expands in the wet weather it will bow badly as it has nowhere else to go. Worse still it might damage the retaining wall.

I feel like it needs to be "floating" in the other direction and only fixed to the house side (the long flat edge closed to the "camera" in the image. Does anyone have any experience of doing this kind of thing and any suggestions on the best way to do it?

I could bring it away from the curved wall by 10mm and use posts instead, but that's quite a lot of work and I feel concreted in posts are going to be just as solid as the wall, so wont actually make it any better!

Decking Drawing

• Jamini
• 27 Oct 2019

 

[martin hill]

Hi there

Dont use a ledger board. Use these on the walls https://www.screwfix.com/p/sabrefix-multi-truss-hanger-50-x-165mm-10-pack/25047. You will only get a small expansion in the wood if it treated timber. So when fitting leave 5/10mm in the hanger.