Extension threshold decking / bifold advice

5 May 2010
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United Kingdom

I'm in the latter part of a single storey rear extension build to the rear of my house. Unfortunately, I've concentrated so much on the extension it never occurred to me what to do outside.

Basically the garden was always a foot or so higher than the house. We had a small patio and retaining wall before the extension.

We have nice new bifold doors now, however no plan of how to link the doors to the garden.

Due to the nature of the build, we have 3 air bricks under the subfloor. I can't find and form answers here. Can we deck over these bricks allowing suitable air gaps and possibly an ACO drainage system?

My plan was to build a raised deck on concrete posts at house and resting in a retaining wall where the grass starts.

Any ideas, thoughts? I know, this is bad planning. My builder has recommended a patio and then retaining wall and steps up to the lawn. Want to avoid this if possible though.


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What height is your dpc? You can certainly have decking if you prefer and it could be level with the threshold. The area under the decking can ventilate the air bricks fine as long as you dont physically block them. You need to consider how the area under the decking will drain water but this can be aall sorts of ways? simple run off to existing areas, gulleys or drainage channels?

Paving would need to be 150mm below your dpc. The dpc is probably above your air bricks but ask your builder. If you have a patio 150mm below dpc you can obviously have a step out of the door above this level but you would need to telescope any air vent through the step to maintain ventilation.

This sort of stuff should have been thought of in the design stage ideally.

Personally i hate decking, it only ever looks good for a couple of years and its a pain to maintain. It is useful for steep slopes and can be useful for level thresholds that havent been designed to allow paving.
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Mmmm first post, dredging up and old topic with a heavy recommendation about a specific product?

Methinks you work for timbertech Andy....

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