New Garage - Probably Permitted Development… Some Questions
Discussion
So, after many years of procrastination, and due to being fed up of the rotten/leaky roof on my current garage getting even worse (I honestly don't think it will last another winter), I have decided that it is now time to finally look at a new garage build…
After much thought, I think I have pretty much decided on what I want - a 3-bay wooden garage. However, I have some queries, and am hoping that the PH collective will be able to provide some helpful advice:
I am planning to do this under Permitted Development. Size I am thinking would be around 11m wide by 7m deep, with a dual pitched roof (front to back) up to the full 4m with 2.5m eaves allowed under PD. Size of the plot is around 3/4 of an acre, so the footprint of the garage is not a concern and will be well under the total 50% allowable under PD (including the existing outbuildings I already have).
So, my queries (so far… I may have more as I go along!!):
1. Trees:
The location for this will be at the back of my plot, quite near a few mature trees. My ideal location for the garage would be around 7m away from the trees at the rear and around 8m from the trees at one side.
Now, some of these trees are covered by an area TPO (some on the side on my own garden, some in a neighbour's garden to the rear of my garden - hopefully that makes sense?). Now, I know that to do any work on trees covered by TPOs that I would need permission… I am not planning to do any work above ground (no trimming, lopping or topping), but the difficulty I foresee here is with the roots - There are a couple of other trees which are not covered by TPOs and other shrubs around the area, so how would I know what roots belong to what trees/shrubs? Would I be required to trace back each and every root to the respective tree (but that would only possibly be feasible for larger roots, albeit even doing that might cause damage when digging around, and what about smaller roots)? Am I likely to cause any real damage to trees with potential roots in this area (apologies is this is a dumb question)? Will the presence of trees covered by TPO being this close to the proposed build negate the Permitted Development route anyway (are there any specific rules on that)?
Note that there is a large single brick garage in the area already, which is sat on a concrete foundation around 8m away from the trees to the side and rear (this garage will be being demolished to make way for the new garage build) - I do not know the spec or depth of the foundations of this existing garage as it has been in situ for many years, well before we bought the property.
2. Building Regs:
Floor area will be well over 30m2, so will still need building regs sign-off, but what do I need to get this? Will they be interested in the tree roots? From the research that I have done, I have seen mention of Structural engineers and Arboricultural Surveyors, but which do I potentially need, or both?
I want to get electrics run to the new garage for lights, sockets, etc., does this need to be covered by building regs, I believe it is? What if I decided to delay getting the electrics run out and installed until a later date, would I still need to include in the original building regs submission (but then would this cause an issue with sign-off if it wasn't done until a later date), or would I need a separate buildings regs submission / sign-off at that later date (so would it be better to just do it all at the same time)?
What else are building regs interested in - foundations (will I need a structural engineer / arboricultural surveyor for drawing up the specs for this)? Anything else?
I will need to get a groundworks contractor in to do the foundations. Wooden garage will be built by the supplier. Electrics will be done by a qualified electrician. I will be insulating, kitting-out and painting/finishing off the inside myself.
Any other thoughts or helpful insights? Apologies for the long post, but thanks in advance for anyone who has read through and can offer any advice!
After much thought, I think I have pretty much decided on what I want - a 3-bay wooden garage. However, I have some queries, and am hoping that the PH collective will be able to provide some helpful advice:
I am planning to do this under Permitted Development. Size I am thinking would be around 11m wide by 7m deep, with a dual pitched roof (front to back) up to the full 4m with 2.5m eaves allowed under PD. Size of the plot is around 3/4 of an acre, so the footprint of the garage is not a concern and will be well under the total 50% allowable under PD (including the existing outbuildings I already have).
So, my queries (so far… I may have more as I go along!!):
1. Trees:
The location for this will be at the back of my plot, quite near a few mature trees. My ideal location for the garage would be around 7m away from the trees at the rear and around 8m from the trees at one side.
Now, some of these trees are covered by an area TPO (some on the side on my own garden, some in a neighbour's garden to the rear of my garden - hopefully that makes sense?). Now, I know that to do any work on trees covered by TPOs that I would need permission… I am not planning to do any work above ground (no trimming, lopping or topping), but the difficulty I foresee here is with the roots - There are a couple of other trees which are not covered by TPOs and other shrubs around the area, so how would I know what roots belong to what trees/shrubs? Would I be required to trace back each and every root to the respective tree (but that would only possibly be feasible for larger roots, albeit even doing that might cause damage when digging around, and what about smaller roots)? Am I likely to cause any real damage to trees with potential roots in this area (apologies is this is a dumb question)? Will the presence of trees covered by TPO being this close to the proposed build negate the Permitted Development route anyway (are there any specific rules on that)?
Note that there is a large single brick garage in the area already, which is sat on a concrete foundation around 8m away from the trees to the side and rear (this garage will be being demolished to make way for the new garage build) - I do not know the spec or depth of the foundations of this existing garage as it has been in situ for many years, well before we bought the property.
2. Building Regs:
Floor area will be well over 30m2, so will still need building regs sign-off, but what do I need to get this? Will they be interested in the tree roots? From the research that I have done, I have seen mention of Structural engineers and Arboricultural Surveyors, but which do I potentially need, or both?
I want to get electrics run to the new garage for lights, sockets, etc., does this need to be covered by building regs, I believe it is? What if I decided to delay getting the electrics run out and installed until a later date, would I still need to include in the original building regs submission (but then would this cause an issue with sign-off if it wasn't done until a later date), or would I need a separate buildings regs submission / sign-off at that later date (so would it be better to just do it all at the same time)?
What else are building regs interested in - foundations (will I need a structural engineer / arboricultural surveyor for drawing up the specs for this)? Anything else?
I will need to get a groundworks contractor in to do the foundations. Wooden garage will be built by the supplier. Electrics will be done by a qualified electrician. I will be insulating, kitting-out and painting/finishing off the inside myself.
Any other thoughts or helpful insights? Apologies for the long post, but thanks in advance for anyone who has read through and can offer any advice!
Equus said:
1. Easy answer is to calculate the Root Protection Area of the trees (fairly simple to do), and to steer clear of that.
If you can't do so, you'll need to take specialist advice. TPO's don't negate PD as such but they're covered by separate legislation, so if you knowingly harm trees subject to them, you'll be liable to stiff penalties. If you need a specialist foundations design, you may need both an arboricultural consultant and a structural engineer, but it depends on precise circumstances.
2. It depends which way you approach it. There are two methods: 'full plans' and 'building notice'. If you're using a design from a manufacturer, speak to them - they should be able to advise and provide you with the information you need for everything above ground.
Thanks, now looking up root protection areas (not heard of that before).If you can't do so, you'll need to take specialist advice. TPO's don't negate PD as such but they're covered by separate legislation, so if you knowingly harm trees subject to them, you'll be liable to stiff penalties. If you need a specialist foundations design, you may need both an arboricultural consultant and a structural engineer, but it depends on precise circumstances.
2. It depends which way you approach it. There are two methods: 'full plans' and 'building notice'. If you're using a design from a manufacturer, speak to them - they should be able to advise and provide you with the information you need for everything above ground.
I want to keep the trees, definitely not wanting to harm or damage them, as all the trees were one of the reasons we bought this property.
CharlesElliott said:
For planning, you would likely be required to get an arborcultural assessment done that would involve a specialist defining a tree protection strategy (fencing) and also root protection areas to prevent machinery etc. damaging roots. Certain areas may need to be hand dug to avoid damage. Your planning would then specify complying with this assessment.
As far as I know, for PD, whilst your obligations not to damage the tree / roots remains the same, no such assessment is necessary so you end up skipping that (formal) constraint.
Thanks, that is what I was thinking. I am wondering whether getting an arboricultural survey done would still be best even if PD (I want to make sure I don't damage any of the trees).As far as I know, for PD, whilst your obligations not to damage the tree / roots remains the same, no such assessment is necessary so you end up skipping that (formal) constraint.
Thanks to the steer from Equus I am looking up tree root protection zones.
smokey mow said:
In short, quite a lot and even more that you’ve probably not even thought about.
At 77m2 that’s a big building and there’s no dispensations for the fact it’s non habitable so you’d have to comply with the same regulations as for any other type of building.
As well as the substructure and superstructure that you’ve already briefly touched on fire is the next major consideration, specifically means of escape, external fire spread and classification of linings. Depending on its location you may also need to think about fire service access and turning provision.
If you’re not confident about your own abilities then you’ll need an architect to help you. The timber frame companies will cover the basics of structural elements but you’ll still need assistance with the remainder.
Thanks for this. Access would not be an issue. As for fire regs, what would apply (is there a site with some easy to understand guidance... i.e. not some 1,000-page technical regs doc!)?At 77m2 that’s a big building and there’s no dispensations for the fact it’s non habitable so you’d have to comply with the same regulations as for any other type of building.
As well as the substructure and superstructure that you’ve already briefly touched on fire is the next major consideration, specifically means of escape, external fire spread and classification of linings. Depending on its location you may also need to think about fire service access and turning provision.
If you’re not confident about your own abilities then you’ll need an architect to help you. The timber frame companies will cover the basics of structural elements but you’ll still need assistance with the remainder.
I know that you can get fire retardant paint/stain for the outside, is that needed/recommended? Would this also mean a ply lined interior would not be possible (i.e. would it need plasterboard or similar)? Would be a bit of a shame if so as ply would be easier / more practical).
I would be getting a side access door fitted, so presumably that covers the escape aspect.
NDA said:
I've had 3 such garages built over the years... I can't help with planning things but would say:
Think about having the garages slightly deeper (longer) than the regular plan. Doesn't have be by much, but it makes a huge difference.
Have a floor above one of the bays - not expensive and incredibly useful for junk!
I painted all of mine black, they sort of disappeared.
Have a 'one key' set of locks rather than 3 different locks for the doors.
That's really good, helpful advise, thanks.Think about having the garages slightly deeper (longer) than the regular plan. Doesn't have be by much, but it makes a huge difference.
Have a floor above one of the bays - not expensive and incredibly useful for junk!
I painted all of mine black, they sort of disappeared.
Have a 'one key' set of locks rather than 3 different locks for the doors.
Was actually thinking about what colour I wanted to end up with, definitely want it to 'blend in' a bit, so was thinking possibly a brown or green shade, with anthracite grey doors... Although the missus seems keen in something less 'dull'!!
Thanks for all the comments and advice, very helpful... Time for me to go do some measuring and more research on RPAs and foundations/piling... I foresee discussions and engagement of the relevant experts in the very near future!
And to answer an earlier question, no there are no pipes, drains, or anything else like that in that area (I checked in the paperwork from when we bought the house).
And to answer an earlier question, no there are no pipes, drains, or anything else like that in that area (I checked in the paperwork from when we bought the house).
Equus said:
GT911 said:
The calculation for the radius of the RPA is 12 times the diameter of the stem at breast height, up to a maximum of 15 metres radius.
... or if they are multi-stemmed trees, it's based on the square root of the sum of each individual stem squared (for up to 5 stems) or the square root of the mean stem diameter squared (for more than 5 stems).That's to make sure your building doesn't harm the tree.
I ran the maths, but wanted to check I got this right (calculated numbers below are rounded to 3dp):
Stem 1 = 2.23m Circumference (therefore 0.710m Diameter)
Stem 2 = 1.93m Circumference (therefore 0.614m Diameter)
Squaring these two Diameters:
Stem 1 = 0.504
Stem 2 = 0.377
Added together = 0.881
and then Square root = 0.939
x 12 for an RPA of = 11.265m
Is that all correct (did I understand correctly on the squaring and square rooting process)?
All the other trees are between 0.3m and 0.6m Diameter, so max calculated RPA of around 8m for any of the others.
That would mean I would need to move the plan over and forward by around 3m from where I had originally thought…
However, one thought, the existing garage is already in that area (i.e. around 8m away from this multi-stem tree) - Would that have any material impact? i.e. the fact that the foundations already in place are 3m into the RPA for this particular tree, and has been there for many years, I'm thinking (but I may be wrong… it has been known!) that there would be very little risk of impact by replacing and expanding (the expansion would be away from the tree line)?
Or to ask a slightly different question, not that this is what I want to do, but out of interest - Could I knock it down and rebuild to same spec? Or in the process of removing the old, would the new still need to abide by the RPA rule?
Or to ask a slightly different question, not that this is what I want to do, but out of interest - Could I knock it down and rebuild to same spec? Or in the process of removing the old, would the new still need to abide by the RPA rule?
GT911 said:
If the entirety of the foundations in the RPAs are existing and you intend to reuse them, then this should help significantly.
The majority of roots are in the first 600 mm of the ground, so it is likely they will have diverted on coming up against the existing foundations, but there is always the chance they have damaged the foundations, depending on the species.
What species of trees are you dealing with?
No idea of the species, there are several different ones - Does bring up a concern though about potential damage to new foundations, even outside of the RPAs... Something to get more details from an Arboriculturalist on then...The majority of roots are in the first 600 mm of the ground, so it is likely they will have diverted on coming up against the existing foundations, but there is always the chance they have damaged the foundations, depending on the species.
What species of trees are you dealing with?
GT911 said:
If you want to replace the existing foundations and you don't intend to change the incursion into the RPAs from what is already there, it most likely will just need a supervised hand dig and replacement of the foundations, the supervision is done by your appointed arboriculturalist.
As an aside, there are solutions for new build over RPAs that a reasonable Tree Officer will be happy with, particularly if the incursion is not too significant.
These are usually some sort of above-root raft that is supported using smallish diameter piling, helical piling is quite good for this sort of thing.
However you wish to proceed, you do need to get an arboriculturalist to properly assess the situation.
Helpful things to consider, thanks.As an aside, there are solutions for new build over RPAs that a reasonable Tree Officer will be happy with, particularly if the incursion is not too significant.
These are usually some sort of above-root raft that is supported using smallish diameter piling, helical piling is quite good for this sort of thing.
However you wish to proceed, you do need to get an arboriculturalist to properly assess the situation.
Equus said:
... but that would take you into the realms, I would suggest, of stuff that you're not qualified to assess. You'd need a qualified arboriculturalist to make such judgements and agree them with the LPA Tree Officer.
Oh, without question, I agree wholeheartedly I am well out of my comfort zone, but nonetheless, all the helpful feedback from everyone is appreciated! 
Time to find a decent arboriculturalist...
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