dimensions on planning as opposed to reality?

[mjc55]

So at what stage does this become an issue, if at all?

 

I am just looking at detailed plans for main house (we are currently building a Pod that we will live in during house build) and looking back at the Planning drawings I would like to slightly modify some of the external dimensions!  Maybe up to 75mm or so to account for cladding.  Is this going to be an issue?  The overall width is 18.8m.

 

In my time as an AT it was never an issue (as far as I am aware at least) but all my work was in extending existing not new build.

 

Any thoughts welcome

[DevilDamo]

The bottom line is you build in accordance with the approved drawings.

[Mr Punter]

You will probably not get pulled up on this.  They often allow a maximum 100mm leeway to work in with brickwork.  If it already built you don't have much option.  If not, just do as @DevilDamo suggests.

[mjc55]

Its the main house that I am looking at currently - not started the build on that yet.

[BigBub]

Each council will have its own published Enforcement Policy and most take the view that proportionate action in relation to a proven breach of planning would only be taken where there is demonstrable harm caused and where it is expedient to do so. Whilst it is unlikely the council would even be made aware of a discrepancy less than 100mm, its also unlikely they would take any action over it as it would be considered de minimus. At most, you may be asked to submit a variation of condition to amend the approved plans, and at worst the changes could be considered material differences which negate commencement of the development and could lead to planning permission being lost. 

[nod]

75 mil or 750 No ones going to come out and measure unless someone complains So crack on

[DevilDamo]

56 minutes ago, nod said:

750

🤔

[Alan Ambrose]

This has been discussed a few times on ‘t ‘ub already. If I remember rightly, the subtle difference between footprint and overall dimensions might help. Also, by convention, the planning drawings are an approximation e.g. they don’t include drainpipes, TV antennas etc and so some interpolation is allowed and expected. Also, a lot of drawings say ‘you shouldn’t take dimensions off the drawing’ or some such which gives you a little more scope. As always, planning enforcement is just your lovely neighbours. You could always put in a non-material amendment if you want to be squeaky clean.

[Dave Jones]

look at the scale of your approved planning drawings, a pencil line thickness is likely to be at least 600mm!

[Temp]

If they send someone to measure you can always offer to hold one end of the tape.

[kandgmitchell]

As mentioned above you are obliged to build to the approved drawings. Do they specifically set out dimensions for the build and to what degree of accuracy? 18.8m could be anything up to 18.85m really, so arguably you could be only 25mm over  Quite honestly I'd be very surprised if the planners got upset by a variation of 0.04% in a dimension caused by cladding thickness; they've got bigger fish to fry.

[Pocster]

😊 . You can go “ as far as you can “ off the original drawings . Without being ridiculous. As mentioned if no one complains I.e neighbor ; no one cares . If you do ‘grab a bit extra ‘ just be prepared to give a reason if caught .

e.g I had this . Neighbor complains house is higher than drawings . Drawings show house against ‘original wall ‘ . The original wall didn’t exist ( I had knocked it down ) - so is my new wall higher than original wall ? . Also ( as a plan B ) I claimed to the enforcement officer that I had added extra floor insulation which had increased the height slightly .

 

As a side note . My build ‘grew’ 1 metre longer and 0.5m wider 

 

Edited July 16 by Pocster

[Oz07]

I must be the only idiot here who put in a non-mat ammendment for 100mm. This is when drawings allowed for 100mm cavs and I decided to build with 150's. I didn't want some clever clogs to come out with a tape and cause me pain afterwards.

[Kelvin]

I had a chat with our BCO about this although it was more about escape window height off the floor. We were inside the regs but I asked him if the cutoff was a hard line (1200mm as I recall). He said he applies some leeway (not everyone does) but at some point he has to say you’ll need to change that. Therefore you build to your plans and the regs. Build slightly outside of that and you might get away with it and probably will but what if you don’t. Could be a disaster for a relatively minor benefit. You can also make a non-material amendment as mentioned above. 

Edited September 7 by Kelvin

[saveasteading]

On 16/07/2025 at 10:08, Temp said:

offer to hold one end of the tape.

But first think what you need to do.

 

I've asked this formally of planners. Half a brick would never be argued against. 100mm.

Also whether they considered you were cheating or it's just reality.

 

Strangely nobody ever builds half a brick smaller.