How to waterproof between brick house and garden bed?

[jules_d]

Hello. We are looking at re-doing the garden beds along the from wall of our house. The building inspector who inspected the house prior to us purchasing it, advised that we install a barrier between the garden beds and house to prevent damp. Would some black polythene sheets be sufficient? How far down should this be applied? 

or is there a better option? 

 

[JacobZ]

Hi @jules_d,

Welcome to the Bunnings Workshop community, it is wonderful to have you with us.

You want the barrier to extend about 100-150mm below the bottom edge of the concrete foundation. This will ensure that water doesn't sit against the side of the foundation where it can be wicked up through the concrete causing damp issues.

I'd suggest digging down below the bottom edge of the concrete foundation and installing this Black Double Wall PP Flute Board with Fastfix 50mm x 5m Waterproof Repair Tape to seal the seams. It is a bit more rigid than builder's plastic, so it is less likely to rip and is a bit easier to install. You can set it in place and then backfill the soil to hold it in place, then seal the top edge to the wall using Black Sikaflex 11FC Purform. If you're struggling to keep it in place before backfilling, a couple of daubs of Sikaflex will help to hold it in place.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob