Information on raft foundation

Sille09

Hi, we recently got planning permission for a t-shaped bungalow with some living space upstairs. At the moment we're getting quotes from builders to complete full job. Some have given more detailed quotes for raft than others and I have a few questions about the raft

What would the normal depth of hardcore under a raft be on reasonably solid ground?
Would the depth of concrete be the same throughout the full raft or would it just be under load bearing walls?

Thanks in advance

Poor Uncle Tom

Your quotations can't be very detailed if they are based on drawings which don't detail structural elements such as the foundations. That is a fundamental part of the design and should have detailed drawings and specification before getting quotations on it.

In other words it's up to you to provide the raft details to the builder to price, not up to a builder to provide a quote to you on an unknown detail. You may be compounding this by asking people on the internet to guess details which are likely based on your individual project.

Please contact a structural engineer about this.

Sille09

Thank you for your reply. Our structural engineer has provided builders with plans for everything that they need to complete a thorough quote. This information is for myself personally so that I can understand these quotes and exactly what work it entails. I am not from a construction background and was just wondering if there were standard minimum regulations. Thanks again.

A fella called fish

Sille09 wrote: »

Thank you for your reply. Our structural engineer has provided builders with plans for everything that they need to complete a thorough quote. This information is for myself personally so that I can understand these quotes and exactly what work it entails. I am not from a construction background and was just wondering if there were standard minimum regulations. Thanks again.

Every foundation design is project specific. I've designed them with different depths of stone beneath, different thicknesses betneath walls/slab and some which are the same thickness throughout - all depends on the layout of the load bearing walls, the magnitude of the loads and the specific ground conditions.

So there is no "standard answer" to your question.

Sille09

Thanks, I think I'm getting the gist of it all now!