Rear Extension Permitted Development - Recommended Drawings?

[noTAGlove]

We are starting the process of building a 3m(h) x 3m(d) x 5.5m (w) extension to the rear of our house. This falls within permitted development so we are proceeding on the basis of building control rather than planning permission.

We will need a large steel across the rear of the house so will have the structural calculations completed in advance.

We have photos of exactly what we want, and have shown those to a couple of builders to quote on that basis. They’ve done plenty of extensions so know what we want.

Therefore, what level of building plans do we now need to support our application? My research tells me that anything from a simple site plan to more detailed building regulation plans seem acceptable to building control.

So, I’m wondering what is recommended by the wise people of TZ, and who have the had do the work. Is there a sweet spot where it’s worth spending a few hundred quid getting some better building plans?

Also, anyone use peopleperhour.com or other similar websites and can make a good recommendation? Or should stay clear and go via a more traditional route.

Ta in advance for any help.

[reggie747]

I'd spend the required amount (2-300 quid) even if only to remove ANY ambiguity and non compos mentis understanding between your builder and yourself.

Your comparative estimates will work better if the hymn sheet is the same too.

It's effectively a box on your house but.... fit, fabric and final finish will be highlighted on plan with full input from yourself to your draughtsman, unless of course your builder is someone who has satisfied you completely in the past.

Let the council have their copies under building notice, they'll check everything's hunky dory and Bob's your Fanny's husband so to speak !

[noTAGlove]

I'd spend the required amount (2-300 quid) even if only to remove ANY ambiguity and non compos mentis understanding between your builder and yourself.

Thanks for that. Bit of a newbie at this so sorry for the stupid questions in advance.

If I pick some skilled draughtsperson or similar from the internet to do some basic plans, how does he/she get the information they need from me?

Do I see photos of the existing rear of the house, some photos of other extension or will I for example get a questionnaire?

[seadog1408]

Do plans, the builder will want them to follow, the council engineer will want to see them and check them against the work on his site visits.
take lots of photos of the progress ie, foundation pour, walls up, steel in place etc as I did This last year and when I approached the council for my completion certificate, the engineer who did the visits had moved on and lost the photos he had taken.

mike

[reggie747]

Do plans, the builder will want them to follow, the council engineer will want to see them and check them against the work on his site visits.
take lots of photos of the progress ie, foundation pour, walls up, steel in place etc as I did This last year and when I approached the council for my completion certificate, the engineer who did the visits had moved on and lost the photos he had taken.

mike

What a tit, they should have been in a log at the council as I'm sure you're aware.

[reggie747]

Thanks for that. Bit of a newbie at this so sorry for the stupid questions in advance.

If I pick some skilled draughtsperson or similar from the internet to do some basic plans, how does he/she get the information they need from me?

Do I see photos of the existing rear of the house, some photos of other extension or will I for example get a questionnaire?

Is there any friend/relative/colleague/neighbour who has had work done anywhere near you or at least in your borough ? Rather than going blind on t'internet, that'd be the preferred route.

Failing that, there must be somebody local to where you live who does plans, scour the local rag paper etc.
They'll come and see you/your home and discuss your requirements on site then go away and return with a completed drawing to your specification.

[Cooper85]

I agree with Reggie747 that a small amount invested in preparing plans and a brief specification is well worth the money.

Not only will it allow contractors to price on a like for like basis and help you obtain more meaningful quotations it could prove to be beneficial during and on completion of the project when agreeing any variations or additional works that have occurred.

Obtaining quotations from contractors based on photographs is high risk and once the project commences you have no real control on what the contractor will install, unless it has been identified in his quotation or specified.

[Guz]

For my sins, I’ve been a structural technician for about 25 years. Although took time out going part time to a Sports Degree.

I would always go the proper route, particularly as ‘we’ need to indemnify our work providing insurance etc. I used to do structural surveys and the number of ‘builders’ who have been doing things wrong all their days is really frightening.

For what you are explaining, our engineers a package called blue beam which provides quick sketch type drawings.

I’m autodacad guy and CadsRC which we use for more detailed work and sharing with others practices.

If needs be send through some pics.

[mangoosian]

From my understanding there are 2 types of drawing

1) planning drawings - these can be pretty basic and are to get you planning consent. If not needed then still worth thinking about going down getting consent if you ever want to sell the place. (Shows buyers all is in order)
2) building control / structural drawings. A professional will do these and they will define materials, beams, calculations, etc. Your prospective builders will quote from these drawings (as material will impact cost. E.g. is it breeze block and rendered? Brick? ) building control will also validate the structural aspects and calculations.

As you will need 2) then I would say get 2) done and use to fill 1) too.

Sent from my [device_name] using TZ-UK mobile app

[TomGW]

And, for my sins, I am a town planner and have been for a lifetime. I can only say that cutting costs at this stage of the process is a recipe for potential problems down the line. Get it designed properly and make sure that you understand what the drawings actually indicate e.g. is the beam to be below the ceiling or above, with a flush ceiling running through. Someone producing drawings without visiting the site and without detailed discussions about your vision is not likely to end well. Get it done properly.

[BCD]

Bennyc is the man to talk to.. 👍🏼

[mindforge]

I have the same conundrum. Can anyone recommend a good draughtsman or similar to do this type of work in London?

[benny.c]

Bennyc is the man to talk to.. 

Ha, thanks mate. Hope all is well. Are you in yet?

[jmarchitect]

And, for my sins, I am a town planner and have been for a lifetime. I can only say that cutting costs at this stage of the process is a recipe for potential problems down the line. Get it designed properly and make sure that you understand what the drawings actually indicate e.g. is the beam to be below the ceiling or above, with a flush ceiling running through. Someone producing drawings without visiting the site and without detailed discussions about your vision is not likely to end well. Get it done properly.

I've lost count of the number of times that I've heard of people embarking on an investment equivalent to a new family car that have cut corners at design stage and have been quick to throw the blame at their builders/building comtrol. To the OP- photographs of what you want won't cut it with building control and will be interpreted any which way by the builders providing quotations. When you are standing in the middle of a building site saying 'this isn't what I wanted' and watching your builder shrug his shoulders, it will be too late to go back and do things properly. Send photographs of your house now and examples of what you want in an email describing what you want to three architect's or architectural designers in your area and ask them to set out what they will do and for how much. You can then choose someone to work with and hopefully enjoy a seemless process. You won't need a planning application but you will need coordinated architectural and structural general arrangement plans, sections and elevations, key junction details, building regulations specification and structural calculations as a minimum. If you are going to send the drawings out for tender to multiple contractors, someone professional really should produce a form of tender directing the tendering contractors to provide their tenders in a certain format that will make comparing the prices easy. The same person should also help you choose between them. That's a bare minimum. Additional services might be help in colour and finishes selection, kitchen design and sanitary ware selection but they tend to be handed out to companies providing a 'free' service and come with the requisite opportunites for confusion, delay and aggravation down the line. All that said, I wish you the very best of luck!

[TomGW]

I've lost count of the number of times that I've heard of people embarking on an investment equivalent to a new family car that have cut corners at design stage and have been quick to throw the blame at their builders/building comtrol. To the OP- photographs of what you want won't cut it with building control and will be interpreted any which way by the builders providing quotations. When you are standing in the middle of a building site saying 'this isn't what I wanted' and watching your builder shrug his shoulders, it will be too late to go back and do things properly. Send photographs of your house now and examples of what you want in an email describing what you want to three architect's or architectural designers in your area and ask them to set out what they will do and for how much. You can then choose someone to work with and hopefully enjoy a seemless process. You won't need a planning application but you will need coordinated architectural and structural general arrangement plans, sections and elevations, key junction details, building regulations specification and structural calculations as a minimum. If you are going to send the drawings out for tender to multiple contractors, someone professional really should produce a form of tender directing the tendering contractors to provide their tenders in a certain format that will make comparing the prices easy. The same person should also help you choose between them. That's a bare minimum. Additional services might be help in colour and finishes selection, kitchen design and sanitary ware selection but they tend to be handed out to companies providing a 'free' service and come with the requisite opportunites for confusion, delay and aggravation down the line. All that said, I wish you the very best of luck!

Amen to that. Ignore at your peril.

The only thing I would add, is to suggest that the tendering process sets out how the 'prelims' are to be priced. These are the items that cannot be accurately quoted for until the builder gets on site and establishes how deep the foundations need to be, how much underbuilding is needed, which pipes may need to be rerouted and any other unforeseen issues are exposed. For example, one builder may include a bare minimum quantity at a higher rate, while another may include a more realistic amount at a lower rate. Indicate that these should be priced per cubic meter concrete / height of underbuilding per metre etc. That way you can see where the differences may lie.