Should I survey (again)

[Mrog]

Hi,

I am planning to convert a brick and stone barn with Q-class permitted development.  As per Q class requirements the vendor commissioned a structural survey to confirm suitability for conversion. This notes minor issues with pointing and roof timbers.

The barn is mostly single storey, with an existing concrete floor which will need to come out.

I am wondering if there is any value in commissioning a further survey, which may just identify the same issues?

I do have a that the foundations may be insufficient (just because it was built as a barn) but if the slab is being replaced anyway think any underpinning required could be addressed at the same time. Welcome others experiences?

[Conor]

What's stage are you at? Viewing, under offer, bought?

[Alan Ambrose]

I might check that the existing structure really allows class Q in your area. Have a guarantee from the sellers? Talked to the planners?

[Mrog]

Thanks @Conor and @Alan Ambrose, the Q-class is confirmed, so planners have accepted suitability for conversion and we have had an offer accepted. 

So I am thinking another inspection survey won't gain us much and we would need a more intrusive (=costly) survey to tell us more (eg foundation condition). 

As the barn is mostly single storey and we will be using a metal roof, we are not adding significantly to the load on the walls and hence may not need significant underpinning if the foundation isn't up to scratch. I wanted to test the logic that additional surveys are unlikely to add much to our understanding with anyone who has similar experience.

Edited August 9 by Mrog

[Jilly]

You/your architect will need to engage a structural engineer and have trial pits anyway.

You could also weigh up going for planning to demolish and replace making the sustainability argument as you have the class Q to fall back on. 
Single story with underpinning can be expensive, if you are lucky the foundations will be adequate. 
If SUDS/bats/archeology /highways can all be avoided with class Q compared to planning permission, you save a heap of headaches and surveys. Conversions also seem to be more lenient with some of the building regs too because of the compromises. 
All the best. 

Edited August 9 by Jilly

[IanR]

10 hours ago, Mrog said:

As per Q class requirements the vendor commissioned a structural survey to confirm suitability for conversion.

 

43 minutes ago, Mrog said:

So I am thinking another inspection survey won't gain us much and we would need a more intrusive (=costly) survey to tell us more (eg foundation condition). 

 

It's unlikely you could rely on the existing Structural Survey. It was not created for you, so you have no recourse to the Author if there's anything inaccurate, unless the Author is in agreement that it can be re-assigned to you. Also, Structural Surveys completed for a planning App are paid for by the applicant and are influenced for a positive outcome.

 

But, to satisfy Building Control, they will need to be convinced that the conversion, including any modifications is structurally sound. The fact that it's stood for many years without falling over is a good start, but any modifications you make changing loads through the structure will require an SE calcs to convince BC. Are you not engaging an SE for this type of thing? They would perform any required survey to base their calcs around.

 

As an aside, there is now a proven route to a full planning approval, using the approved Class Q as a fall-back, this would likely allow you to make improvements over and above what the Class Q is allowing and provide a better conversion in the long run. You do however have to watch the clock as you are on a time limit for completing the Class Q, should a subsequent Full Planning Application get rejected.

Edited August 9 by IanR

[ToughButterCup]

28 minutes ago, Mrog said:

.... I wanted to test the logic that additional surveys are unlikely to add much ....

 

The only reason for doing any more survey work is to assure risk reduction.

And the only question to ask is - of those to whom you will pay money -  who will require further evidence, and in what format do they need it? 

For example

• no foul drain, no dwelling - Percolation Test  (aka 'Perc Test')
• Structural Engineers (SEs)  suck their teeth - a lot : more even than plumbers - Ground Condition Survey  (aka Have some cores done)
• Bats? GCNs? Lesser Spotted Uninhabited Barn Dweller?  Stage One Desk Exercise ( aka Ecology Survey)

Wince and bear it. Sorry. 

Ian

 

[Mrog]

Thanks all for the useful perspectives. I recognise the inherent risk of bias in the original survey and prefer to pursue the Q class route to avoid all the additional demands that full planning will bring.

Fully expect to need an SE to validate Architects detailed plans in due course. As @ToughButterCup notes it is really about a risk/cost trade at this stage, where I could still argue for a reduction in price or as a worst case walk away.

[Conor]

You'd be better off doing a walkover with an experienced builder and even architect and SE. A RICS survey has a set scope and format, and they'll all tell you the same thing. But you won't know really until you start digging and ripping things apart. Just assume worst case and budget accordingly.

 

Edited August 9 by Conor

[Alan Ambrose]

In a day, you could actually do a perc test and dig down by the foundation to see how deep it is and/or core the slab. That would give you new info.

[LSB]

I have class Q and it was passed as structurally sound.

But when it came to BC and SE drawings it had to be underpinned.

It has stood since the 1950's and is only single storey like yours, so be prepared for this eventuality and how expensive underpinning is.

 

 

[saveasteading]

On 09/08/2024 at 09:10, Jilly said:

Conversions also seem to be more lenient with some of the building regs too because of the compromises. 

Seem? The regulations apply. Some are relaxed. But it is insulation not structure.

A survey for planning only confirms that the building is fit for conversion. 

There is every likelihood that some structure needs strengthening. 

Speak to the SE who did the survey. They may give you some free first impressions.

You need serious advice. Practical from a builder experienced in this, but also technical from an SE and that has a fee..one for an overview and then for the detail.

 

Does the building look sound?

What part of the country? 

 

 

[Jilly]

4 hours ago, saveasteading said:

Seem? The regulations apply. Some are relaxed. But it is insulation not structure.

A survey for planning only confirms that the building is fit for conversion. 

There is every likelihood that some structure needs strengthening. 

Speak to the SE who did the survey. They may give you some free first impressions.

You need serious advice. Practical from a builder experienced in this, but also technical from an SE and that has a fee..one for an overview and then for the detail.

 

Does the building look sound?

What part of the country? 

 

 

Sorry, I was going off piste. I was meaning that we didn't have to have a SAP certificate or to comply with part M for example. I was surprised, and would also that check this has not changed. 

[saveasteading]

On 09/08/2024 at 11:28, Conor said:

assume worst case and budget accordingly.

Underpinning is very expensive. Dig 1m of pit, tunnel under footing, bring in or mix  0.5m3 of concrete and fill. Wedge up tight to footing. Repeat....

Could be £500/m so not to be taken lightly.