I need a solicitor

WE have had an issue with a tiling job that was done on our new home build. We have a third party report from Bostik indicating the tiler did not perform the necessary moisture test in preparing the floor for installation and he failed to install expansion joints, as a result the tiles on the main floor are lifting. He claims that it was the in-floor heating that was turned up and caused the floor to dry too quickly. He indicates the fact that the tiles on the second floor are not lifting is evidence of this, but the installation process on the second floor is totally different because it is a wood floor so the moisture from the concrete doesn't apply.
We are in need of a low cost lawyer who will see this case through for a set fee as we are looking at huge cost to replace the entire main floor tiling but can't pay 6000-7000 for a solicitor.