New Patio has caused a crack in house wall

Salopsian

https://forums.moneysavingexpert.com/discussion/comment/82162845#Comment_82162845

Thanks, your diagram makes sense. I will check the green area indicated tomorrow.

Not really sure what I should do in this situation.

Is it best to call in a structural engineer, or should I have a drain survey? [the downpipes for the roof and garage both exit under the gate and then pass along the side of the house at the corner in question, could a drain problem have triggered subsidence?]

Should I dig out some more by the foundation blocks to investigate further?

Section62

https://forums.moneysavingexpert.com/discussion/comment/82162882#Comment_82162882

Personally I'd probably not do anything for the time being. We've just had an exceptionally dry summer (unless you're in Scotland) so a bit of seasonal movement isn't unexpected. After enough rain when the ground becomes more hydrated it is possible the cracks will close up again.

If you start investigating then when you renew your insurance you might feel obliged to declare a possible subsidence issue - whereas at the moment it could just be thermal movement, or a bit of settlement since the house was built.

Don't lie to your insurer, and don't ignore what's going on. But keep an eye on the wall and see what happens next.

If constructed properly your house should have foundations a lot deeper than where you've been digging for the patio. To get any meaningful information you'd need to dig to the level of the bottom of the foundations, and that could be a big hole. Better to leave that to the professionals if the need arises.

WIAWSNB

In the worst case, I'd hope the house is still under a building warranty?

uknick

https://forums.moneysavingexpert.com/discussion/comment/82162932#Comment_82162932

What he said. Before I paid for an engineer to check the house, I'd start a warranty claim to get a free inspection.

daveyjp

The cracks look minor to me, just monitor them.

On a 5 year old build it is likely still settling. Cracks across bricks also wouldn't too much of concern. Like everything else, bricks are now made to a price and will fail.

Salopsian

https://forums.moneysavingexpert.com/discussion/comment/82162932#Comment_82162932

It has 10 year NHBC warranty, not sure what that means in practice tbh.

Salopsian

Thanks for your advice, it's really helpful. I'll leave it for 6 weeks and then take some more photos, see what's changed.

The thing that troubles me, is that there was no crack over the dry summer, they began appearing once it began raining. As there are no slabs down yet, it is pretty wet and it got flooded after a heavy downpour. This is what made me think there is something wrong with my patio 'design', not sufficient drainage, causing water to build up against the house wall and around the foundations (the soil is clay and I packed it, together with some gravel, against the house wall as my understanding was need a solid base for the patio). Is this also a possible cause?

Salopsian

thanks, will do. Not sure how this forum works. Can I post more photos in six weeks times or will this post be 'closed'?

Albermarle

https://forums.moneysavingexpert.com/discussion/comment/82163407#Comment_82163407

Posts are usually left open, so you should be able to update in 6 weeks.

Boohoo

https://forums.moneysavingexpert.com/discussion/comment/82163403#Comment_82163403

The ground shrinks when dry and swells when it rains but the ground could be solid so not absorbing the rain as it needs to a steady amount of rain water and will just run off if a downpour happens.

Have you asked your neighbours if they have had any issues like your house?

What part of the country are you?