We have a new build home on clay in North Shropshire.
Just before the outbreak of Covid-19 (before the end of the 2-year snagging period), I informed the builder that we had heard a very large crack. On inspection, we found a number of large stress cracks in the drywall in a bedroom where the wall is supported by a RSJ extending across two pillars. There was also evidence of a broken external brick and cracks in the brickwork.
Detailed investigation has had to wait until my wife came out of shielding. Removing a section of the drywall shows that the internal breeze blocks are also cracked and the window board has dropped at one side.
The RSJ has been checked and found to be correctly sized etc so this week the investigations have moved to digging test pits around the house. All the work has been under the direction of a Chartered Structural Engineer.
This morning I think that we have an answer.
It would seem that during construction, the builder has correctly sized the foundations in a wall that is located near a hedgerow. The problem is that the builder has run the deep foundations level for about 15ft and has then taken out the difference in the required foundation depths in one step in a 90 degree corner (which supports one end of the RSJ where the broken brick etc have been seen.) I am advised that under Building Regulations the change in foundation depth should have been done in a number of step changes to cope with different soil dynamics.
To date, I have not advised my house insurer of the ongoing investigations as nothing has actually been done to the property but I am struggling to know what to do if the structural engineer comes back with a requirement to underpin. I am told informally that underpinning is likely to be needed under the foundations where the two levels meet extending forwards and around a patio door that sits under and forward of the RSJ.
Clearly, this fault has nothing to do with subsistence or heave as such. The builder seems to accept that the onus is him to put things right but I do not want to end up with paying extra insurance premiums for what is a major building fault.
How best do I protect my interests? Grateful for any thoughts/advice.