why screed

[greengrass]

Concrete kitchen floor. original covering red quarry tiles. overlaid with vynil tilles by previous owner of property we overlaid with airflow/cusion style covering.
Had local floor covering shop come in to measure and price up wetroom floor covering, just measured up never checked what they would be laying covering on or if it was sound. Now on their second visit they are saying the floor has to be screeded at extra cost, is it because of existing vynil floor tiles. Screeding will make the floor higher than adjoining rooms.

I now wish I hadn't called them in they seem reluctant to explain what's going on and threaten to take our large deposit if we cancel claiming they have already cut the floor covering they are installing.

[collectors]

I would check in the small print to see if there is anything about the sub floor being suitable. If you have nothing in writing that explains this, you should be able to have a full refund of your deposit. Remember an estimate is just that & a quote should be the total price.
Any quotes or estimates that i have given for my work has always been final & never altered unless the client has a change of mind to what is being done. If they are any sort of tradesmen they should have seen if there was going to be a problem from the outset & allowed for it, or at least explained what could happen.