Can decks be installed above the damp proof course (dpc) of my home level with a door?
The dpc exists to prevent dampness rising into a dwelling and should never be compromised or bridged. This is why one often sees advice to install decks well below dpc level particularly where the deck is a DIY project. However, decks can be installed level with doors or patio windows using the following technique:- 1. A ledger board (joist) is fitted to the wall using exterior grade bolts with galvanised or plastic washers around the shank to create a minimum gap of 10mm to allow water to run freely down the wall. 2. It is important to keep this gap clear of leaves and dirt etc which might bridge the dpc. 3. The deck support joists are then fixed to the ledger board using joist hangers. The joist framework should have a fall of 1:100 away from the property and have good ventilation underneath. 4. Deck boards should be fitted at right angles to the ledger and with a 6mm gap between each board.
