okay OP, people have helped me before here, and I may be able to help someone for a change.
we sold our house this year. when it came to the engineers report of the purchaser, it showed that the drains needed to be replaced. in fact, it was slightly more complicated because one of the drains ran under the kitchen and we needed to have some underpinning done to that as well.
we could have claimed this under our insurance, but at the moment (post floods/big freeze etc) we were told by insurance company that the claim would take up to a year to process. so we decided to bite the bullet and pay for the work ourselves. i guess it was a gamble, because the buyer did not enter a legally binding contract (we would have preferred that). but we decided we had to do it as we could not sell it to anyone else in the future knowing that this work needed to be done and could lead to structural damage if we didn't rectify it. evidence of the problem existed previously ( a crack) and it was interesting two that of the three estate agents we spoke with before selling, two suggested covering up the crack!!! We went with the third because he seemed the fairest in every way anyway.
So next began the most interesting exercise of my life. I know nothing of the construction industry. We spoke to the 5 main ground engineering contractors in our area. Quoted prices varied form €11,000 to €45,000. 3 out of the 5 suggested (2 strongly) that the best thing was to effectively falsify an insurance claim. Those same three gave one price for insurance claim and one price if we paid ourselves. One of the 5 gave one price for cheque and one price for cash. Given the current climate they were all willing to start the following week.
Anyway, we went with the €11,000. We also got an engineer to supervise. That was the wisest thing we ever did, as the contractor was only interested in cutting corners.
In the end, the work took two weeks, the purchaser was happy but did two more drains tests as she was entitled to do. Thankfully the sale went through.
So to answer your question, why not get the vendors to do the job on the house and if you feel you don't want to lose the house, get in a legally binding contract for both parties conditional on the work being done to the satisfaction of both your engineer and theirs.
If they are like us, they will be just happy to sell, they will want to do a fair job (we didn't want this young girl buying a pup) and everyone will be happy in the end. We took the hit and have pretty much forgotten about it now. Life goes on...
