Structural Designs and Building Control

[dum_asyousee]

I'm looking for some advice.
I have a project. The build is with ICF Nudura.
A company has issued drawings for me and proposed a private building control for a full plan application
I show the most detailed drawing I have.
Now at the project start I am told I should not have trench foundations. As well I'm told I should have a drainage market and proposed on the drawing.
Can someone advice?

I spent money to have trenches filled back as BCO was not happy with digging this close to the tree (like 1 m) and he said if we go to 2.4m depth the question is of the stability of the trees which are not mine. I have bought rebar to reinforce the foundation which is not on design but speaking to BCO over the phone it was suggested. I'm being told by the drawing provider that is normal stuff to have design changes as you start to build.

 

[Notch7]

A company has issued drawings for me

who did the drawings?

the cross sections look like std cut n paste jobs -dwgs too small to see really

I spent money to have trenches filled back as BCO was not happy with digging this close to the tree (like 1 m) and he said if we go to 2.4m depth the question is of the stability of the trees which are not mine. I have bought rebar to reinforce the foundation which is not on design but speaking to BCO over the phone it was suggested. I'm being told by the drawing provider that is normal stuff to have design changes as you start to build.

the drawing provider if he did a site visit wouldve seen the tree -so no need to only find out when you start digging

Did you need planning permission? -I wonder if you need a tree survey.


If you do get to use a trench foundation, you probably wont be allowed to use a solid floor - it will need to be block and beam

deep foundations are dodgy -I know builders do them down to 2.4m but deep founds carry safety risks.

if the ground is ok, you might be able to have concrete pads and steel beams. or of course you can do piling.

 

[freddiemercurystwin]

Yea can't read those details, those wall constructions look odd, the plans show hardly any info, some dubious notes.

 

[dum_asyousee]

thank you Notch7 for your reply.

Planning permission:
Yes. Planning permission in place with a comment from the Tree and Landscape Office the trees are not subject to TPOs and quote here:

'These trees are not protected, and have no wider landscape importance, and in this respect, the application should not be constrained by what are trespassing branches and roots from these trees.'

The back-right wall of the house is within 10m distance from the TPO-protected oak and would require a trench depth of 2.4m I was told in accordance to guidance. No mention by the Tree and Landscape Office report if it would be an issue to dig in this distance to the tree.

Site visit:
I have proof of invoice paid to the value of £200 for a site visit to do the measurements. At this point, I was asked if two manholes present under planned development I wish to be moved from under the structure and I said yes.
I was queried about another 3rd manhole for which I was not sure of its purpose and if it is functional (at the moment I can tell it looks like a groundwater manhole about 400mm deep, but probably not functional as less than 500mm from a tree).

Foundations:
Yes. So now BCO advises that I have looked into piling as an alternative which I'm doing. The front wall of the extension would be within 3-4 m from the 9m cypress and 8m cedar. And 1 m from the foundations there is a slope with a small retaining wall that runs at roughly a 1:1 gradient.

Ground: medium shrinkable clay

So in the next few weeks, I expect drawing. The old company offers drawings for free. But do I want to deal with them?
Another engineer said I get them in two weeks and we meeting Wednesday. With piling company prebook following week.

All I want to know. I spend about £3-4.5K in materials, I no longer need, labour to fill back an inspection trench and on top of that I need a new set of drawings. Should I expect any compensation or do these things happen and I need to take this on the chin?

 

[dum_asyousee]

oh yes that build is with ICF from Nudura.

 

[^woody^]

All I want to know. I spend about £3-4.5K in materials, I no longer need, labour to fill back an inspection trench and on top of that I need a new set of drawings. Should I expect any compensation or do these things happen and I need to take this on the chin?

You should expect a competent designer to have realised the site issues and constraints and have advised you or designed to allow for them.

Whether that does mean that the designer is negligent and therefore responsible, would depend on your contractual arrangement and what was said or not said in your conversations and instruction.

In context, clients are advised to have (and pay for) a ground survey, then the ground conditions are unknown and it would be common for inspectors to require foundation changes when they actually see the trench. That's a common risk. But any designer would be expected to look around and notice trees, shrubs and drains - all of which can influence foundation design, and to take them into account.

Your plans seem to be generic and not specific to the site.

 

[Murdochcat]

Given the comments above a private building inspector is probably not a good idea.

How much would your local BCO charge

 

[dum_asyousee]

Local BCO: last year I think it was around £500 and this year similar. Private was more expensive and I was told better value for money.

woody: Thank you for comments. I have never been advised by anyone about the ground survey to be done. I don't remember the exact conversations. I have email exchanges and such.
My understanding was to have everything in place for the build and I had that in the email before the quote was given.
As well the fact that I paid the required amount in May and got my drawings in December doesn't grow confidence.

To all thank you for your comments guys. I guess the problem shared = problem halved. I start to think it's just a bump on the road to happiness

 

[Notch7]

I know its a bit late now, but its possible to get a reasonable idea the influence trees have on foundation depth using this calculator.

building inspectors used to carry tables with them to work out depths

Its worth noting that for people who have been told "youve got an oak trees x metres from property, you need to go x silly metres deep" if you think your soil is good, get a soil analysis done and if you have solid ground you might get away with shallower foundations. I had thi son a job, the client got a soil analysis, it turned out to be mudstone and he only needed to go 800mm deep not the 1.8m the BI said.