Steel frame barn conversion

[Craigjm]

Good morning.

 

Firstly thank you to everyone on this site who contributes, there is certainly a wealth of experience on here.

 

My build.

 

After what seems to be a long 2 years we are almost in the position to start converting our 4 bed class Q barn conversion.

 

We are currently awaiting the 2.5 acre of land to be signed over into our names that my in-laws have so kindly gifted to us.

 

I am now at what seem to be a crossroads in decision making, our plans have been drawn up that state we need to use a castle therm raft method for the foundations, this seem to be very costly but I am led to believe that this method is to provide support to the steel frame that needs to be left in place as part of the permitted development and will need to be installed in bays which is going to cost upwards of 17k.

 

Ideally I would like to use the block and beam method as suggested by my builder which comes in considerably cheaper.

 

Can anyone offer any advice on which route would be better? I am considering the idea of applying for full planning so I can remove the full frame but I would like to know if there are any other suitable options.

 

I have attached a 3d image we have had done for reference if that helps.

 

Thanks in advance.

 

 

 

 

[Temp]

Beam and block is really just a floor system. The castle raft them sounds more like underpinning for the frame or have I got that wrong. 

[Craigjm]

58 minutes ago, Temp said:

Beam and block is really just a floor system. The castle raft them sounds more like underpinning for the frame or have I got that wrong. 

According to my drawings the steel frame could be in danger of collapsing if the entire foundations is excavated in one go as we have to excavate approximately 1m to in depth to allow for adequate head height inside, to solve this issue the structural engineer has planned to excavate in 5 separate bays constructing one at a time (obviously causing more time and money) this is where I have become a bit stuck on what to do next.

 

The steel frame really is a bit of a nightmare as it will not provide any structural element to the build at all, it's only purpose will be to sit within my cavity wall. ??‍♂️

 

I am contemplating applying for full planning so I can remove it completely but I am not sure how the cost will balance out.

 

Edited December 1, 2020 by Craigjm

[Dave Jones]

id listen to the builder and do block and beam on strip footings. they could accro up the legs easily while the conc set.

 

No brainer if the steel is decorative only.

[Jason L]

Be mindful that there are strict rules when it comes to the existing structure under Class Q ( i.e. .  it has to be capable of conversion ) so be guided by your design team not the builder.

[Craigjm]

Thanks for the info and ideas I will run this by my architect and structural engineer.

 

I don't suppose anyone has any information on the cost implications of obtaining full planning permission after permitted development? I may have to consider this as an option if it saves a considerable amount on the foundations.

 

Thanks again.

[Mr Punter]

As @Jason L says, you may well not get full planning consent.  Can you get your architect to talk to the planners?

[Craigjm]

1 hour ago, Mr Punter said:

As @Jason L says, you may well not get full planning consent.  Can you get your architect to talk to the planners?

 

Yes, I have had a word with the architect and he is going to try and find some cheaper alternatives or ways around it, hopefully he will come back with some good news.

 

He has told me that with us having to excavate 1m down essentially the castle therm raft will act as a water tight "basement" like system as the ground surrounding the barn is going to be higher than the internal floor.

 

My builder has suggested that digging around the barn and levelling off the surrounding ground should in theory prevent the need to have the raft system in place.

 

I guess I will have to wait and see what happens.

 

Cheers.

 

 

 

 

 

[PeterW]

22 minutes ago, Craigjm said:

He has told me that with us having to excavate 1m down essentially the castle therm raft will act as a water tight "basement" like system as the ground surrounding the barn is going to be higher than the internal floor.

Considered a new architect ..???? He has happily drawn (including that lovely 3D rendering) that the floor levels are the same inside and outside .. which if you need that sunken raft is not the case ..

 

I am sort of with your builder on this, but I would be checking a few things first. I would get a machine in and excavate down the inside about 300mm in from one of those legs, and check how far down the foundations to, and more importantly how far out.

Farmers are well known for the “that’ll do” method of groundworks, and you could find that those legs are stood on 100mm thick pads, or cubic metre blocks - all will depend on what day it was, and who was paying for the concrete... That will cause you problems for any walls, not just your legs as you can’t remove the concrete without some serious work. 

Have you got a structural engineer and a structural survey for the existing frame ..? That may be useful before you go digging tens of cubic metres of soil out to find you can’t get close to the legs. 
 

 

[Temp]

If you decide to apply to knock down and replace I think it would be important NOT to claim this is "necessary" as that could undermine your Permitted Development. Class Q buildings have to be "capable of being converted". Better reason would be that it allows a greater level of insulation.

[Temp]

Ok so things are a bit clearer. If you decide to press on with the frame then...

 

The SE clearly believes the steel frame needs some sort of under pinning. Thats kinda a separate decision to the floor make up. You could go back to the SE and ask if more conventional strip foundations can be used to underpin the frame together with a beam and block floor.

 

Some sort of decision needs to be made about the ground level outside. Either leave it high with tanking (how?) or excavating down and perhaps putting a French drain around the outside.

 

I'd suggest both issues should be discussed at a meeting/zoom call with you, the SE, Architect and builder. It might be they have good reasons for suggesting the existing design, if not then the outcome should be a decision that either the Architect or SE should produce a revised foundation design drawing that takes into account both issues.

Edited December 1, 2020 by Temp

[Craigjm]

2 hours ago, PeterW said:

Considered a new architect ..???? He has happily drawn (including that lovely 3D rendering) that the floor levels are the same inside and outside .. which if you need that sunken raft is not the case ..

 

I am sort of with your builder on this, but I would be checking a few things first. I would get a machine in and excavate down the inside about 300mm in from one of those legs, and check how far down the foundations to, and more importantly how far out.

Farmers are well known for the “that’ll do” method of groundworks, and you could find that those legs are stood on 100mm thick pads, or cubic metre blocks - all will depend on what day it was, and who was paying for the concrete... That will cause you problems for any walls, not just your legs as you can’t remove the concrete without some serious work. 

Have you got a structural engineer and a structural survey for the existing frame ..? That may be useful before you go digging tens of cubic metres of soil out to find you can’t get close to the legs. 
 

 

The 3d render was constructed for viewing purpose as to give us an idea of what the barn will look like once finished, the actual elevation of the ground goes up by roughly one meter to the far end of the barn on the drawing which isn't properly shown.

 

I believe the legs are to be excavated to check the depths prior to works starting. From what I can tell on the engineers drawings a new frame is to be erected along side the existing on top of the concrete form work that will be part of the foundation raft.

[Craigjm]

11 minutes ago, Temp said:

Ok so things are a bit clearer. If you decide to press on with the frame then...

 

The SE clearly believes the steel frame needs some sort of under pinning. Thats kinda a separate decision to the floor make up. You could go back to the SE and ask if more conventional strip foundations can be used to underpin the frame together with a beam and block floor.

 

Some sort of decision needs to be made about the ground level outside. Either leave it high with tanking (how?) or excavating down and perhaps putting a French drain around the outside.

 

I'd suggest both issues should be discussed at a meeting/zoom call with you, the SE, Architect and builder. It might be they have good reasons for suggesting the existing design, if not then the outcome should be a decision that either the Architect or SE should produce a revised foundation design drawing that takes into account both issues.

 

Thats great advice.

 

I think that's possibly the best solution as I am getting very mixed opinions from all involved.

 

Thanks very much ??

 

 

[LSB]

If you apply for knock down and rebuild and get refused then your class Q will still be in place as long as you don't say it is because the barn is not sound, but for another reason like eco credentials.

But, I would suggest looking at your local planning portal to see if anyone else has done the same successfully, after all there is no point spending money if no chance of success.

The other option is to have a pre-app meeting with your LPA, after our Class Q app was refused twice I did this and the report they sent was great, explaining what we would need to do to be considered for planning, which we did and it was approved on the 3rd attempt.

But, in our location we have been told that the barn must be structurally convertible and that planning would never (never say never really) be approved for a rebuild.

This is because our barn is in the countryside and it would count as a new house in the country.

Ironically, we also have a low roof, but we are not allowed to dig down as we have to use walls, floors and roof and only repair when totally necessary.  The roof is going to be replaced as the current one leaks and is not worth repairing.  The only digging out we are doing is where the floors are not level and we have already been told to leave 4 inches around the outside wall to keep the walls up.

Ours already has walls inside from being a pig building, but we can do as we wish there so they are probably coming down.

 

[Craigjm]

4 minutes ago, LSB said:

If you apply for knock down and rebuild and get refused then your class Q will still be in place as long as you don't say it is because the barn is not sound, but for another reason like eco credentials.

But, I would suggest looking at your local planning portal to see if anyone else has done the same successfully, after all there is no point spending money if no chance of success.

The other option is to have a pre-app meeting with your LPA, after our Class Q app was refused twice I did this and the report they sent was great, explaining what we would need to do to be considered for planning, which we did and it was approved on the 3rd attempt.

But, in our location we have been told that the barn must be structurally convertible and that planning would never (never say never really) be approved for a rebuild.

This is because our barn is in the countryside and it would count as a new house in the country.

Ironically, we also have a low roof, but we are not allowed to dig down as we have to use walls, floors and roof and only repair when totally necessary.  The roof is going to be replaced as the current one leaks and is not worth repairing.  The only digging out we are doing is where the floors are not level and we have already been told to leave 4 inches around the outside wall to keep the walls up.

Ours already has walls inside from being a pig building, but we can do as we wish there so they are probably coming down.

 

 

Thanks very much, there really is a lot of great advice on here, I definitely a great deal to consider moving forward but Jesus the time it's taking is crippling as are the rules you are confined to which some seem quite unnecessary.

 

Would I be right in assuming that there would be another fee to submit for full planning? Even after already having obtained permitted development?

[Russell griffiths]

I’m a bit baffled by a lot of this class Q stuff. Can you iron out a few things for me. 

 

I applied for full planning and had a site meeting with the planners, 3 months later we had planning, since that day I have not seen a single person from the planning dept. 

The next man on site was building control to inspect our foundations. 

 

So bear with me here. 

You get the foundation design you want passed by building control, you then take down the steel frame completely, excavate out pour the foundation you want and put the frame back up. 

 

I bet the building regs guy wouldn't give a hoot the frame wasn’t there. 

 

Am I missing something. 

[Craigjm]

8 minutes ago, Russell griffiths said:

I’m a bit baffled by a lot of this class Q stuff. Can you iron out a few things for me. 

 

I applied for full planning and had a site meeting with the planners, 3 months later we had planning, since that day I have not seen a single person from the planning dept. 

The next man on site was building control to inspect our foundations. 

 

So bear with me here. 

You get the foundation design you want passed by building control, you then take down the steel frame completely, excavate out pour the foundation you want and put the frame back up. 

 

I bet the building regs guy wouldn't give a hoot the frame wasn’t there. 

 

Am I missing something. 

It's all a bit of a mystery to me why there are so many obstacles in the way of the build as a whole.

 

As I understand the main purpose of permitted development is to maintain the existing structure and as a result of this conversions are easier to obtain than full planning.

 

The only thing left standing on my barn will be the original steel frame which as far as I can see serves no purpose to the structural design, everything else will be new which the LPA are fully aware of.

 

I would be lying if I said I haven't thought about the idea of just taking the frame work down but we are worried of the risks that could cause without full planning.

[LSB]

14 minutes ago, Craigjm said:

 

Thanks very much, there really is a lot of great advice on here, I definitely a great deal to consider moving forward but Jesus the time it's taking is crippling as are the rules you are confined to which some seem quite unnecessary.

 

Would I be right in assuming that there would be another fee to submit for full planning? Even after already having obtained permitted development?

yes, generally the fee for a full app is about 450.

Our planning was approved in May, with contamination surveys as a condition.  These have just been completed and I have submitted planning for discharge (£116).

I've been investigating and estimating since May and haven't finished, don't be fooled about how long it takes and how many decisions you need to make.

In my investigating it would be much easier to build from scratch using timber frame or SIPS, I would if I could.

11 minutes ago, Russell griffiths said:

I’m a bit baffled by a lot of this class Q stuff. Can you iron out a few things for me. 

 

I applied for full planning and had a site meeting with the planners, 3 months later we had planning, since that day I have not seen a single person from the planning dept. 

The next man on site was building control to inspect our foundations. 

 

So bear with me here. 

You get the foundation design you want passed by building control, you then take down the steel frame completely, excavate out pour the foundation you want and put the frame back up. 

 

I bet the building regs guy wouldn't give a hoot the frame wasn’t there. 

 

Am I missing something. 

I'm sure you are right, if no one reports you, but there are some small minded people out there.  I'm watching a local farm because I'm a bit suspicious about what they are doing.

 

We are very careful what we say to people, particularly as we are replacing the roof, which is not against the app, but is on the edge.

[Tosh]

We've done something very similar though ours had full planning, not Part Q. The key is the word 'conversion'. We submitted a variation to try and remove the frame but the planners refused it as they said removal and building afresh from the ground up would constitute a 'new build' which was against policy in the open countryside. So we had to keep the frame and the concrete slab but could remove all the cladding etc. So we've designed it such that the frame will be hidden within the ICF walls and fortunately we have enough building height to build up from the slab and not compromise head room.

If I were doing this again I wouldn't bother putting myself through the pain with the planners, it just isn't worth the time and effort IMO.

 

WRT the steel stanchions there's no underpinning as the stanchions are not carrying any significant load so the pad foundations are more than adequate for the conversion. We plan to dig trenchfill between the columns which will take the bulk of the external wall loadings.

 

Hope this helps.

[Russell griffiths]

So let’s say you don’t fancy taking it down

 

why not buy a dozen 4m lengths of rsj 

dig a  metre square hole next to each steel leg and put the rsj in, fill with concrete

get a mobile welder out to weld some cross bracing in between the two chunks of steel

so in effect you can completely undermine the whole barn

dig out what you need, pour your preferred floor

then cut off the temporary supports re bolting the steel legs back onto the new floor 

cut the temporary rsj down to ground level 

 

bobs your mothers brother. 

[Tosh]

14 minutes ago, Craigjm said:

I would be lying if I said I haven't thought about the idea of just taking the frame work down but we are worried of the risks that could cause without full planning.

 

I too thought this and given our remote location and good neighborhood relations maybe we could've got away with it. But it's a big risk if it turns sour and could prove very expensive. I was told by one planning consultant that on some part Q jobs he'd done they even had to leave 'viewing windows' in strategically placed points in the wall so that anyone wanting evidence could see that the frame was still within the construction. Thankfully we don't have to do that.

 

It's all bonkers I know but I took the view it only takes one call from someone to the planners and, well, who knows. Depends on your risk appetite I guess.

 

[PeterW]

Once the weight is off the legs you can dig out around each one but it will take a while - I like the idea @Russell griffiths suggests, and you could even make it reusable and do a leg at a time but it all depends on the below ground conditions. That could be an expensive hole you are digging ... 

[LSB]

9 minutes ago, Tosh said:

 

I too thought this and given our remote location and good neighborhood relations maybe we could've got away with it. But it's a big risk if it turns sour and could prove very expensive. I was told by one planning consultant that on some part Q jobs he'd done they even had to leave 'viewing windows' in strategically placed points in the wall so that anyone wanting evidence could see that the frame was still within the construction. Thankfully we don't have to do that.

 

It's all bonkers I know but I took the view it only takes one call from someone to the planners and, well, who knows. Depends on your risk appetite I guess.

 

about 4 years ago someone a few miles from here had class Q for a conversion and decided that a new build would be easier, but didn't apply.

Either someone reported him, or the planner drove past, but it got back to the council and when they attended site there was no barn.  So, they removed the permission saying that it was to convert and barn and as there was no barn there was no planning.  

 

[Tom]

1 hour ago, LSB said:

about 4 years ago someone a few miles from here had class Q for a conversion and decided that a new build would be easier, but didn't apply.

Either someone reported him, or the planner drove past, but it got back to the council and when they attended site there was no barn.  So, they removed the permission saying that it was to convert and barn and as there was no barn there was no planning.  

 

+1 for this. If you remove the barn structure there will be nothing left to convert.

Definitely worth looking at full planning, and as suggested above use the argument for better insulation, eco credentials etc. rather than the difficulty in converting - you'd have had to prove the opposite presumably to get the part Q in the first place. I guess you have outlined your plan for conversion for the part Q, deviation from this might raise eyebrows - but as stated above, who would check?

Full planning very much depends on your LPA though. Ours seem quite open to this as we were successful. Don't forget you'd save a bit on the VAT for a new build too.

[Temp]

If you can afford the time then I think I would also go for a knock down and rebuild.

 

Your situation is somewhat unique in that they are already allowing the external appearance to be significantly changed by removing the cladding. I think the key to a new application would be to argue the end result would be identical to the conversion already permitted. So avoid any temptation to change the design at the same time. Perhaps even use the same drawings. 

 

Ideally find an appeal that allowed a similar case and submit it with the application.

 

I'd like to think the planners could turn this around in 8 weeks but depends how pedantic they are.