Patio drainage beside an extension build - am I being overly concerned?

[unhombre]

Briefly, I have made a patio about 8ft X 20ft in front of a kitchen extension which, I am told was 'hastily erected'. It slopes very very gently down toward the extension.

I didn't use a membrane underneath the slabs as I was fearful of water drainage from rain running down into the foundations and causing damage. The cost though is that I have to weed between the slabs regularly. Which is a royal PITA to say the least.

Was I being overly concerned? Would rain drainage actually harm the extension foundations? I'd love the answer to be 'no', as I would happily spend a day raising the slabs again and laying a membrane to at least resist those lovely weeds.

any obs. gratefully received.

You can lay a membrane like terram100 which lets water through but not weeds. Google geotextile woven fabric.
I would have thought the fall of the patio towards the house would cause damp rather than a structural issue so consider sloping the fall away from the house if you can.

oh thanks for that fabric tip, tricot! I thought of the reverse slope thing, but it will bring questions re levels of surrounding stuff eg lawn edge and garden borders.

But I think it's a good idea still. Just means 2-3 days of digging and clever level-changing techniques! But tbh anything is better than crawling across the slabs every two weeks!

thanks again, and will get on with the terram100 membrane.

Terram is probably top of the range - it is used for road building and reed beds etc. Im sure you could find something similar/cheaper at b&q or similar. It is like black dressmaker's interfacing iykwim.

yes ikyym. Getting it flat at least, or with a slight'ish slope away from the extension will be great. It's york stone flags, so it'll be a long heavy weekend, but prob. worth it for 1 peace of mind and 2 A LOT less weeding.