Can I fill the trench in my garden?

cleol56

Hi there,

I have a foot deep trench running along the back wall of my house (about 4.5 metres long and 0.5 foot wide). Inside the said trench is a drain and some clear air bricks. I assume the trench is there for this reason and as people have built patio over patio for many years the ground has risen and the trench has been created. Am I right in assuming this?

We are looking to revamp our garden and would like to get as much floor space as possible as it is so small.

Is it ok to fill the trench with something like gravel or cover it with a grate of some kind or will this stop the airbricks from working?

Any advice would be greatly appreciated.

stator

What sort of drain? A private rainwater drain? A sewer?

cleol56

Thanks for the reply. It is just a standard outside rainwater drain.

Mojisola

cleol56 wrote: »

I have a foot deep trench running along the back wall of my house (about 4.5 metres long and 0.5 foot wide).

Inside the said trench is a drain and some clear air bricks. I assume the trench is there for this reason and as people have built patio over patio for many years the ground has risen and the trench has been created. Am I right in assuming this?

Is it ok to fill the trench with something like gravel or cover it with a grate of some kind or will this stop the airbricks from working?

Don't fill it with anything - not unless you want to deal with damp problems in the house.

Even covering it with a grate will reduce the airflow.

The real answer is to dig up the patio and take the level back to the original. We had to remove three layers of patio when we redid our garden because of the height increase - each previous owner had just laid their choice of slabs over the ones already there.

Hoploz

If the new ground level would be above your damp course level (if you have one) or the floor level, or would block air flow to the void under a suspended floor, do not fill it in.