Building close to trees

[malcolm]

Following on from a recent garage thread, do you think it might be possible to convince a council and building regs to let you build a carport near a tree?

I'm in a conservation area so need tree reports before I can apply for planning permission. The tree report that came with the house had a root protection area of 9m from the tree (a willow) and said no building was allowed in that area. A later tree report that I funded suggested the building could be 6m from the tree (mostly because I wasn't going to fund it if the report didn't say that).

Currently I have a car park extending to around 0.5m from the tree and have secured a temporary marquee on top of that to house 4 cars from the winter weather.

I have a lot of cars and have been down a number of blind alleys with my garaging arrangements and they just don't work without a car port where the marquee is. I'm thinking oak frame with a nice small plain tile roof. It would be useful if it could house 4 cars so building regs would need to be involved.

I suppose I could speak to the tree report writers, the tree bloke from the council, and building regs. Council will probably be good if I convince the tree report people. Building regs will want 6 billion metre foundations which will create a loop.

Anyone on here with tips or suggestions about how to proceed? My current thought is to bodge and sell the place and buy somewhere with less rules, but that's daft as nothing I could possibly do will kill that willow.

 

[Feltwell]

If it's carport rather than a garage, presumably you'll only need foundations under the support posts, rather than all the way along the walls as with a garage. So - my thought is - can you convince the tree people that smaller, localised footings that only exist under the support posts will not damage the tree roots to any meaningful degree?

Building regs should be able to tell you how far down you have to go. 450mm below original soil level (i.e. after any later oversite has been dug away) is generally the minimum I believe, but it depends on your soil type and being so close to the tree may make a difference! Alternatively, for even less intrusion on the tree roots, driven piles could be used (but these will be expensive). My local Building Inspector was quite friendly and approachable when I did my garage - is it worth a call to your local BC office and see if they will have a pre-application conversation?

 

[Flyfisher]

Who really knows how these red tape things work?

My immediate thought is that a basic car port would require little more than a bucketfull of concrete under each post and therefore not trouble any tree, but I appreciate the hoops we're required to jump through these days.

I've no idea what the relevant authorities will require, and I doubt anyone does without those hoops being jumped through. However, what I can say is that our previous Hertfordshire house was on a small development within a totally protected wooded area. Not only were all trees protected but hedges and other 'substantial' flora as well - all with the express intention of protecting and maintaining the mixed woodland nature of the area. Our front garden contained a mature oak as well as hornbeam and hazel and half of the rear garden was full of mature hornbeam and ash. The protection was so 'complete' that we were refused permission to thin out some of the hornbeam to allow the trees to spread their branches. Consequently, they were very tall but 'thin'. The front garden oak was similarly unable to really spread out and was tall and thin for an oak, even though its diameter was about two feet at the base, so still a substantial tree. It towered over the house, as did all the other trees, especially the Ashes.

None of that prevented us getting planning permission (on first application) to build a two storey side extension to the house, which brought the building footprint even closer to the front garden oak in question. The house wall ended up about 12-15 feet from the front oak tree and a little more from a similar oak in the rear garden.

Planning consent required there be no damage to the trees (as expected) but otherwise there were no special considerations. The architect (who had worked on other houses in the same area) specified 2m foundations because of the proximity to trees and building control was perfectly happy with that. We lived there for about 15 years after the works and experienced no tree-related problems with the house or the extension and the trees didn't seem to suffer either.

So, based on that experience, I'd say that a carport should be no problem - but that's no guarantee of course.

What I would say is that we found our architect through personal recommendation of neighbours who had done similar things and so he was quite knowledgeable about the local planning regime and what would and would not be acceptable, which probably helped us getting permission at the first attempt. An architect might be overkill for a car port, though if it helps smooth the planning issues then it could be money well spent. Unfortunately, there's really only one way to find out.

Best of luck.

 

[88v8]

I am a bit of a tree nut. In our previous house, we had an extension built. Near one front corner there was a old prunus which I was not prepared to damage, so we kicked in the footprint to avoid it. When I say 'near', it was about 30in from the corner of the finished extension bay. It 'interfered' with the builders' access to the extent that I made them cut their scaffold boards around it rather than lopping branches.
We also had a 25ft stand of cobs about 15ft from the side of the house and a 25ft holly, 8f' from the garage, and in our 0.3 acre garden there were about thirty full-size trees none of which were protected, they were there because I wanted them.
So I come at anything involving trees, on the presumption that trees outrank buildings.

Now willow make a gorgeous tree, but.... they are very thirsty, and I would not want one near my house, even if it's annually pollarded to limit its water demand. The roots are shallow and can spread 100' radius. Drains... arrgh.
Any foundations near a willow would need to be massive & very deep.
Or, very minimal.

In your situation I would avoid any works that would damage the root plate. Metposts if you can get them in, and no slab. Loose paving on membrane. No foundations, no slab, no sub-base. After all, what matters is the roof, yes? So just focus on the roof, and do nothing or next to nothing in the ground.
Then there will nothing to object to, and no damage to the tree or your wallet.

Ivor

 

[malcolm]

That's a good idea! If I build the car port under 30m2 then I won't need building regs and that will make the foundations predictable.

Building regs will worry about settlement and demand huge foundations which might be incompatible with the tree and would trigger archaeology. All I'm worried about is stopping the car port from blowing away which metaposts or similar should achieve perfectly well. If I leave the existing tarmac base in place the tree won't notice any difference. I'll see if I can get that past the tree consultants.

I wouldn't choose a willow. This one was huge. The rear of the house has 3 inches of settlement and I'll need to relay the drains this year. I'm planning to make it a bit smaller each time I get permission to reduce it and will hopefully end up with an ornamental willow.

 

[Feltwell]

I'd be a bit wary of using Metposts - it will be a huge point load using standard Metposts, it must be well over a ton of roof tiles for a carport that large, plus the structure. I'd at least cast the Metposts into concrete blocks to spread the point loading, else I can see you having a twisting, sinking carport eventually.

Another thought - if 30m2 is not large enough (it wasn't for my garage) are two carports very close to each other a possibility? I'm just thinking that for a car to stay completely dry, it will have to be parked a fair way in from the side of the carport - if the car staying completely dry is the objective, rather than just keeping the worst of the weather off.

 

[malcolm]

I would need to be careful about ground movement too. The existing tarmac covering has probably raised 2 or 3 inches immediately beside the tree since it was laid in 1970s ish. The posts would need to be able to move independently, an attempt at a slab or raft probably wouldn't work. Some localised concrete foundations would probably be sensible though.

30m2 is nowhere near big enough. Keeping the willow leaves off is the main requirement for the car port, but it's in a sheltered area and works well for rain too. I'm hoping to build a further 3 car garage in the future (in the short term modify the shed in the same location so at least I have some sort of indoor workshop).

My original plan had been to use the barn with the bad roof as a workshop but the other half wants to use it as a kitchen. That would have avoided the need to build near trees and I already have planning permission for that option. Could be worth another think.

 

[88v8]

Whatever 3m of hardwood firewood weighs, I have it sitting in a shed supported on four 30" x 4" Metposts. Two tons perhaps?

If in doubt, just use more Metposts.

Ivor

 

[livias]

I can 't remember where I read it sorry - Conservation area rules / Tree protection zone rules (most likely) / Beds BC rules but you are allowed to encroach on the tree proection zone so long as it is not too much. My dodgy memory suggests 20 per cent of the area. So some sort of carport on pillars should be feasible.

They don't like you driving directly over the protection zone either and you would have to put down some sort of permeable ground protection too

 

[88v8]

They don't like you driving directly over the protection zone either .....

Quite rightly. Roots require both air and moisture, and vehicles driving over the root plate cause deep compaction of the ground, which harms the roots and damages the health of the tree. Plants with shallow systems, such as birch, and willow, are particularly vulnerable.
Compaction can be rectified, but it's expensive.
http://grounds-mag.com/mag/grounds_maintenance_treating_soil_compaction/

Ivor

 

[malcolm]

I was hoping not to have to dig up the car park which has been there for 30 years. Though I could imagine it is allowable to park in the car park at the moment but that rules say parking there would damage the tree if I put a roof on it.

 

[livias]

You don't have to dig up car park which is already there - at least I was not told to do so - It is only if you are covering over / driving over open ground that protection is called for