‘Weak mortar’ causes new homes to crumble

Taylor Wimpey has been forced to carry out remedial works on a number of new-build homes after the mortar crumbled.

The problems were highlighted by a BBC investigation which found that poor mortar had caused cracks to appear in homes on a Taylor Wimpey development in Scotland. It said that similar issues were uncovered on at least 13 estates built by various commercial housebuilders around the country.

Taylor Wimpey told CM it carried out quality assurance tests on all the mortar it used but that there are "rare occasions where issues do arise".

NHBC, which provides warranties for new homes, said it was "sorry" about the problems. It said mortar performance was a “complex issue” because it can be affected by a number of issues, and that its inspectors check performance on properties at various sub- and superstructure stages as part of its inspection process.

It explained that in order to establish whether homeowners have a valid claim, the performance of the mortar needs to be established for an individual property and assessed against the normal weathering that would be expected for the age of the building. 

Testing is generally carried out by a visual assessment and lightly rubbing the mortar with a traditional flat head screwdriver in locations with visible erosion and undamaged areas. Laboratory mortar analysis is only considered in certain situations.

Traditionally, mortars were specified by the volume proportions of cement, lime (if used) and sand but there are now a number of factory-made mortars which rely on different mix proportions. "It is important that the analyst has all the information relating to the type of mortar used to avoid assumptions being made which may result in the mix proportions being misinterpreted," the NHBC said.

A Taylor Wimpey spokesperson said: “Quality assurance tests are carried out on the mortar used on all of our sites and there are very few instances where it fails to meet the required standards. The mortar we use in the construction of our homes complies with building regulations and is of sufficient strength to meet the structural requirements of the houses and garages. We want to reassure our customers of our absolute commitment to delivering excellent quality homes and achieving high levels of customer satisfaction. On the rare occasions where issues do arise, we endeavour to resolve them as soon as practically possible.”

A statement from NHBC said: “We are sorry that some homeowners have had problems with their new homes. As the UK’s leading warranty provider we care passionately about the quality of new homes and are committed to helping homeowners resolve any problems they may have.

"As a warranty and insurance provider, we work with builders to help them improve the construction quality of the homes they build. However, it is the builder who is ultimately responsible for the quality of the new homes they build.”