Planning a home extension, where to start?

[fourstardan]

Dumbass question but do you as an Architect work out the build estimate then take your %?

[z4RRSchris]

Architect to draw plans, planning, and then a scope of build should be in the region of 5-7k for that build.

the shell should be circa 2k sqm, but as its small might be tight, finishes ontop so budget 3k.

EDIT: just looked at your plans, knock through, new kitchen, etc etc. its a 100k by the time you've finished the two floors.

process:

architect
structural eng
planning
scope / tender doc
party wall if needed
interview contractors
sign JTC
either you certify the contract or pay a QS to.

they will then ignore the drawings, material selection and generally fk it up to a point you vow never to do it again. in 10 years you'll have forgotten this and think its about time to do it again.

Edited by z4RRSchris on Monday 15th January 12:09

[GreatGranny]

Looking at your plan, trying to get proper stairs into the attic will be hampered by configuring the stairs to get the sufficient head height in the attic.
I suspect that's why they have used a spiral staircase so it exits in the attic with the highest ceiling height ie. the centre.

But Architect will be able to advice on this.

As other posters have said, £80k won't be anywhere near enough to do everything you want.

[Equus]

z4RRSchris said:

process:

architect
structural eng
planning
scope / tender doc
party wall if needed
interview contractors
sign JTC
either you certify the contract or pay a QS to.

they will then ignore the drawings, material selection and generally fk it up to a point you vow never to do it again. in 10 years you'll have forgotten this and think its about time to do it again.

You've missed preparation and submission of Building Regulations drawings, which usually happens as a separate process after Planning... and unless there are particular difficulties anticipated, we wouldn't normally get a Structural Engineer involved until that stage (ie. after Planning, instead of before).

Your second-to-last sentence sounds familiar, though - builders generally seem to think that following the approved drawings is optional.

[Sheepshanks]

Blimey re the architects fees! We had a two storey extension, inc moving the stairs and the design fee, and building drawing and getting through planning, were just under £2K total inc VAT, done as two separately changed pieces of work. Planning fee on top. This was 2021, build was 1H22.

Didn't have any further contact with the architect once planning was approved until he came to look and see it finished. He did visit an insane number of time at the design stage, although their office is close by and he more or less passes us on his way home.

Our builder did comment that the building drawings and spec were quite basic - adequate for the fabric but light on detail. He wasn't bothered but it meant he had to be told as we went along what sort of internal doors we wanted etc and the electrical stuff, lighting etc, hadn't been spec'd in any detail

Also had £750 structural engineers fees but a chunk fo that was changes we thought about making to the first floor, relating to moving the stairs from the centre of the house to a new location, but in the end we didn't change it so we now have a rather large landing and hall upstairs!.


When the architect revisited he did quiz us about his pricing - he said he's told he's too expensive quite a bit, but I guess for extensions a lot of people are using "plan drawers".

[Mark V GTD]

The jiffle king said:

Can I ask what you get for this?
- Ideas of best layout
- Drawings?
- quantifies of materials?
- Any level of project management?
- Getting it through planning support?

The 8% is essentially for a full Architects service from inception to handover. This would include:
Feasibility
Sketch design
Final design drawings for planning application
Acting as agent in planning process
Working (technical) drawings package (full construction drawings, lighting and power layouts etc).
Specification document
Site inspection service throughout the build and attendance to details such as bathroom designs, joinery etc.

This assumes the client pays for a measured site survey and appoints a structural engineer of course. At this level a QS would also be employed to do a take off and carry our the valuations throughout the build and agree the final account with the contractor.

Sheepshanks said:

Blimey re the architects fees! We had a two storey extension, inc moving the stairs and the design fee, and building drawing and getting through planning, were just under £2K total inc VAT, done as two separately changed pieces of work. Planning fee on top. This was 2021, build as 1H22.

Incredible that you could find a Registered Architect to do that for so little money - not really sure how he makes a living. I work from home (one man business with 35 yrs experience) and my fee would be around £2,700 just up to planning stage (no technical drawings or documents).

fourstardan said:

Dumbass question but do you as an Architect work out the build estimate then take your %?

No - I am not qualified to do that and there would need to be a QS involved at this level (£500k build cost).

Edited by Mark V GTD on Monday 15th January 13:00

[z4RRSchris]

you wont get that for 12sqm

[The jiffle king]

Mark V GTD said:

The jiffle king said:

Can I ask what you get for this?
- Ideas of best layout
- Drawings?
- quantifies of materials?
- Any level of project management?
- Getting it through planning support?

The 8% is essentially for a full Architects service from inception to handover. This would include:
Feasibility
Sketch design
Final design drawings for planning application
Acting as agent in planning process
Working (technical) drawings package (full construction drawings, lighting and power layouts etc).
Specification document
Site inspection service throughout the build and attendance to details such as bathroom designs, joinery etc.

This assumes the client pays for a measured site survey and appoints a structural engineer of course. At this level a QS would also be employed to do a take off and carry our the valuations throughout the build and agree the final account with the contractor.

Sheepshanks said:

Blimey re the architects fees! We had a two storey extension, inc moving the stairs and the design fee, and building drawing and getting through planning, were just under £2K total inc VAT, done as two separately changed pieces of work. Planning fee on top. This was 2021, build as 1H22.

Incredible that you could find a Registered Architect to do that for so little money - not really sure how he makes a living. I work from home (one man business with 35 yrs experience) and my fee would be around £2,700 just up to planning stage (no technical drawings or documents).

fourstardan said:

Dumbass question but do you as an Architect work out the build estimate then take your %?

No - I am not qualified to do that and there would need to be a QS involved at this level (£500k build cost).

Edited by Mark V GTD on Monday 15th January 13:00

Thankyou, thats helpful and also clear that is for commercial clients not residential which is what we would be.
The full construction drawings I guess take a lot of time/knowledge/experience as lighting, power requirements etc are tricky items
Very insightful

[Equus]

The jiffle king said:

Thankyou, thats helpful and also clear that is for commercial clients not residential which is what we would be.

Most clients for residential extensions that we deal with are only interested in design work up to planning and building regulations stage. Whilst we offer a full service (at cost, obviously) they are seldom willing to pay for detailed specifications, tendering, contract management or site supervision.

They are also not usually willing to pay for a quantity surveyor to price the work, which as Mark says is something that lies outside the architect's scope of expertise. Again, we offer the service, and explain the potential benefits, but the majority of domestic clients just see pricing as something they can get a buiilder to do for free (which isn't entirely true).

Though as a result costs would be significantly less than the 8% of contract total he mentions (but I agree with his assessment that the £2K quoted by Sheepshanks is simply not doable, these days.

We quote on an individual basis and some jobs are a lot more straightforward than others in design terms, even if the build cost is similar, but the last one I quoted for a 2-storey extension (a couple of weeks ago) was pretty much exactly twice that for Planning and Building Regulations (including measured survey, but not including application fees or structural engineering).

[GYTRDave]

We are currently in the process our having a large extension done, it's a first for both me and my wife, neither of us having really an idea on what to expect going.

Pricing can vary wildly based on your location, fit and finish, but this is our costing so far.

Work being undertaken:
Remove/demolish detached garage.
2 storey extension to side of property and rear with large single story kitchen extension.

Basically ground floor will be a garage/man cave with games room, bathroom.
1st floor with me large master bedroom with ensuite with enlarged family bathroom opposite and a small library+office for the wife.


Definitely start with an architect, all in ours cost 3k, but it really was worth every penny as they helped spot issues, places where our idea could be maintained while saving etc.

However long you think planning will take, add 3-5 months onto it.
Seems a common theme when looking online, with most people having delays with planning and issues needing sorting.

For us we needed a build over agreements for water and waste pipes, we also, by order of Welsh Water, needed a £500 cctv inspection on said pipes, that was meant to last 4 hours, but took them 15 minutes.

This revealed that some of the old clay pipes had partially collapsed, which we needed replacing at our expense.

Work has now started with the new pipes being put in, footings start Wednesday.

Total cost is 130k plus or minus 10k.

Any questions just ask, if I can help I will.

[Mark V GTD]

The jiffle king said:

Thankyou, thats helpful and also clear that is for commercial clients not residential which is what we would be.
The full construction drawings I guess take a lot of time/knowledge/experience as lighting, power requirements etc are tricky items
Very insightful

You're welcome - the client is commercial but the house will be high specification (central London location) so a good amount of detailing needed (£3m selling price). The difference between this and a private client is there is less 'hand holding' required so we wont be having multiple meetings about what style of light switches will be used. But that decision (and may many others) still has to be made of course!

[z4RRSchris]

hardly comparable a £3m house to a lads 12sqm extension, he needs a 3-5k architect.

Paying £7.5m to the architects on our build, not exactly comparable

[Mark V GTD]

My fees are around the £2.5k mark for London extensions. I was only responding to the query about percentage fees with that illustration.

[DickyC]

Planning a 4.5 x 5.5 single storey extension we hired an architect, he produced the drawings and his engineer mate checked the calcs. Complications included access and us wanting a small utility room and the adjacent aged kitchen extension's roof to line up. Then we tried to find a builder. Very little interest. A few dubious lads came round and pulled numbers out of the air. Then we found a reputable builder prepared to quote. Lovely, buildery sort of bloke, came round, measured up and a few days later a very detailed quote arrived. £80,000 + VAT for the groundwork, footings, shell and roof. That was it. His suggested contingencies for windows, doors, heating, electrics, rough screed and plastering brought it up to £160,000 without top screed, flooring, skirting or decorating.

Abandoning the architect's work, we went with a local firm of conservatory builders who built a 4.5 x 4.5 orangery, all in except the floor and decorating, for £60,000. We compromised on the utility room and old kitchen roof. Jeez, they did work hard and did a lovely job.

It might be worth considering. Anyone thinking about a single storey extension should give it some thought as an alternative to architect and builder.

[goingonholiday]

Gone through this process twice. You need to look at what you are trying to achieve and how complex is it. Do you need a ford or a rolls royce?

We engaged an architect first time around, ended up paying for his time, didn't even get to planning. He simply didn't understand or didn't listen. Switched to a local tecnician who did planning and building regs drawings for much less cost (over 10 years ago so costs won't help). Plus he understood what we wanted.

More recently I did it myself, no planning was required. Structural engineer for the calcs then a few hours reading the regs and bought a scale ruler from amazon. Building regs drawings by hand, then scanned and uploaded. Building control officer was more than happy with them and was very helpful.

Might not work if you've got something complex but for most bog standard residential remodels / extensions its just not complicated!

[Milner993]

Lots of big numbers and percentages floating about, frightening some of them!

I've got an architect coming over at the weekend to discuss ideas and costs, so hopefully il have a better idea of where I stand.

My wife mentioned looking at an orangery extension and keeping the extension to a single story, do you need internal doors from the main house to the orangery like you do with a conservatory?

I'm hoping the Architect will have a rough idea on costs for all options, I don't want to end up in a situation where I've spent a small fortune having plans drawn up only to find that the costs to have said plans built are beyond my budget.

[DickyC]

Milner993 said:

Lots of big numbers and percentages floating about, frightening some of them!

I've got an architect coming over at the weekend to discuss ideas and costs, so hopefully il have a better idea of where I stand.

My wife mentioned looking at an orangery extension and keeping the extension to a single story, do you need internal doors from the main house to the orangery like you do with a conservatory?

I'm hoping the Architect will have a rough idea on costs for all options, I don't want to end up in a situation where I've spent a small fortune having plans drawn up only to find that the costs to have said plans built are beyond my budget.

No. It becomes an integral part of the house. Plus, the footings were dug to take a second storey if required later. The only oddity is the amount of flat roof now. We had to use a different insurer because the percentage of flat to pitch was too high for the old company. Speak to the conservatory people first, it may save you the cost of an architect. The rep has computer games on his laptop that knock up your extension in minutes.

[smokey mow]

DickyC said:

Milner993 said:

Lots of big numbers and percentages floating about, frightening some of them!

I've got an architect coming over at the weekend to discuss ideas and costs, so hopefully il have a better idea of where I stand.

My wife mentioned looking at an orangery extension and keeping the extension to a single story, do you need internal doors from the main house to the orangery like you do with a conservatory?

I'm hoping the Architect will have a rough idea on costs for all options, I don't want to end up in a situation where I've spent a small fortune having plans drawn up only to find that the costs to have said plans built are beyond my budget.

No. It becomes an integral part of the house. Plus, the footings were dug to take a second storey if required later. The only oddity is the amount of flat roof now. We had to use a different insurer because the percentage of flat to pitch was too high for the old company. Speak to the conservatory people first, it may save you the cost of an architect. The rep has computer games on his laptop that knock up your extension in minutes.

If you don’t have doors then it won’t meet the criteria for exemption from the building regulations and so the same requirements will apply (thermal, structural, fire safety etc) exactly the same as if it was an extension.

[DickyC]

smokey mow said:

If you don’t have doors then it won’t meet the criteria for exemption from the building regulations and so the same requirements will apply (thermal, structural, fire safety etc) exactly the same as if it was an extension.

It's a proper extension, built by a conservatory firm, who use builders. Planning permission, building regs, numerous visits during construction, everything. All legal and above board, no exemptions required.

£60,000 using a conservatory firm versus £160,000 using a builder. Admittedly, it's a metre narrower.

And we wasted a few thousand on the architect with our original idea. It is definitely worth considering as an alternative.

I sense I will be pressed on this, so I'll dig out the paperwork.

[smokey mow]

DickyC said:

smokey mow said:

If you don’t have doors then it won’t meet the criteria for exemption from the building regulations and so the same requirements will apply (thermal, structural, fire safety etc) exactly the same as if it was an extension.

It's a proper extension, built by a conservatory firm, who use builders. Planning permission, building regs, numerous visits during construction, everything. All legal and above board, no exemptions required.

£60,000 using a conservatory firm versus £160,000 using a builder. Admittedly, it's a metre narrower.

And we wasted a few thousand on the architect with our original idea. It is definitely worth considering as an alternative.

I sense I will be pressed on this, so I'll dig out the paperwork.

I wasn’t questioning you. Just pointing out to the OP that it won’t be exempt if that’s what they were hoping for so as to save some money.