We're planning an annex build (~120sqm) which we'd like to build to Passivhaus spec, using DIY raft foundations and Isotex blocks. I'm struggling to find a structural engineer to design both foundation and walls to Building Regs. Some engineers can do one but not another. 

 

Are there any reccomendations for DIY-friendly structural engineers who can take on a project like this? Engineer location isn't important. The project location is Surrey / West Sussex border.

1 hour ago, Pavel K said:

Some engineers can do one but not another.

Hard to see why they can't. Don't want to perhaps.

Capital E or small e Engineers?

 

Have they said they cant do it, or are they disinclined to get involved with the system perhaps?

There will be a fair bit of research required before designing Isotex.   Others on here know them and may have more to say.

If the SEs  have looked up Isotex and seen 'liquidation'  that must be discouraging I'd think. 

I'd be inclined to decline too, unless I was short of work.

Pick a better icf system and they will recommend the engineer. 

Same with the insulated slab, pick a good product and they will have details of engineers familiar with the product. 

The worst thing you can do is pick an engineer that isn’t familiar and is over cautious because of this, could cost you thousands in over the top reinforcement. 

We have an option to use an engineer for a given raft system and Isotex also provides an option for a company that can do the calculations for walls and openinings. Separately both options are possible without a problem. What I am after here is a single person / company to work with rather then be in between a few structural engineers who have different opinions on the same project. This is a first of a number of buildings we're planning to build on this site so I'm looking for someone to work with for a few years to come. 

1 hour ago, Pavel K said:

rather then be in between a few structural engineers who have different opinions on the same project.

Fair enough, but Engineers are well used to picking things up from others. If you get yours to do the liaison, then they will be sure to get the suppliers' responses in the right format, see to the integration and check out that it works for your circumstances.

 

BUT, if I was that Engineer, I would have a lot to learn, as duty of care, about your proposed systems. Also wary of adopting any problems or issues arising from their use.

 

I suggest you very politely ask the people who have declined, to explain their reasons, and if they can suggest any other way forward.

 

The definition of raft varies, but my understanding is that a 'passive raft' is usually a kit. ie you are going for 2 kits that are designed to make self-build easier and reduce consultants' input,but at a premium for the kits. Others here know more about these systems.

2 hours ago, Pavel K said:

This is a first of a number of buildings we're planning to build on this site

did you tell the SEs that?

I looked at trying to undertake training for both ICF and insulated slabs.

 

The slabs were easy enough - the insulation just acts as a slightly springy subbase. But I could not get any good information from the ICF industry group. As I understand it, it's just a reinforced concrete design so there are only a handful of design checks unless it's a very large building. 

Thank you all for your opinions, it looks like SEs orchestration is the way to go. 

Have you tried Brian Peacock from Gurney Engineers? He did my Nudura build, not sure if he could do the raft though....

http://www.gurneyce.com/

He is in Surrey so in your area

Edited September 28, 20233 yr by Haylingbilly

Thank you for suggestion, I'll reach out to Brian to see if he can help.