block cavity block construction

[djq]

Hi. We are currently having a 3m x 3.5m extension to the rear of our property and then knocking through the existing rear wall into the kitchen to create a family room.
The foundations are complete and the build underway and I was surprised when I arrived home today to find the builder using a block cavity block construction. We have asked for the extension to be rendered at the end of the build but was under the impression from the start,that the exterior wall would be made of brick in spite of this.
I am going to confront them tomorrow about this but being a novice in this was hoping for some advice.

Is block cavity block a common method of construction if rendering afterwards.

[welsh brickie]

Its quite normal to use block externally if its going to be plastered.
mainly because it quicker and cheaper.
its down to thermal value what block he uses, thermalite or similar is usually used internally but it also depends on the cavity insulation aswell.
Concrete blocks usually laid externally.
He didnt have to inform you what materials he uses,But the building control officer will be able to give you more information upon request.

[TheDoctor5]

Last year 64% of the questions asked in our forum were answered within our DIY project pages at www.diydoctor.org.uk/projects.htm The project pages are now separated alphabetically and your answers are accompanied by diagrams and the ability to see, and buy, the tools and/or required to complete your project. Use our search box to look for your answer and save a great deal of time and money!