Devis is miscalculated

[Ron Avery]

Not sure where to put this, legal, owning or renovations, but I have accepted a Devis for part of the renovation of my roof.  This devis is for the removal and replacement of the ardois and new guttering and down pipes.  The building will be smaller when it is finished as half it is being demolished.

The unit prices per M2 looked OK and so did the overall estimate amongst the others for new framing etc, The lauzes have been stripped and I paid for that bit of the job as new ardois will not be fitted until after the builder finishes new walls and collar etc

 Anyway a friend asked to buy my old lauzes, which the roofer did not want, and I told him there was 175 m2 there and showed him the devis, he said he thought that this seemed a bit big, so we measured it.  We then found that the roofer in calculating the length of he building and sq metres had taken each beam as 1 metre apart when in fact they are 0.6m which makes the length 14 metres and not the 21 metres he has done his calculations on:  So the total quote should be for stripping 100m2 instead of the 175m2 quoted for.  The area for replacement has also been similarly overstated by about a third.

Two questions before I shake his throat

Is it normal to overdo the size to make up for overlaps on ardois, and if not,  what do I do, given that I have waited four months for him to do anything at all.

[Babnik]

Have you spoken to him? It could be just an honest mistake.