Foundations

ElderWanderer

Quick question.

Later in the year I'll be starting (and ideally also finishing) a timber extension to the kitchen. For planning enforcement purposes, it will be a shed.

The plan is to make it almost entirely out of timber, aside from the insulation and roof covering. Partly this is to reduce weight, partly it's because wood is a lot more sustainable than concrete, and partly this is because I couldn't lay a block to save my life but can throw together a robust timber structure without much trouble.

My back-of-the-envelope Google assisted calculations put the total weight of the structure at about 1,500kg all in for approximately 8 square metres-ish. This compares to 3,900kg or so for one built from hollow concrete blocks, and 7,000kg odd for the same structure built as a double skin cavity wall. In comparative terms therefore, it's going to be light as a feather.

For a relatively light structure and good soil conditions, is 600mm foundation likely to be sufficient? What I can find suggests the minimum depth should have the bottom of the foundation below the frost line, which seems to be around 450mm.

It's going to be entirely DIY so consulting a structural engineer just isn't going to happen.

delly

Sorry, but you can't get structural advice on boards, as it may leave the site liable for incorrect advice.