Estimating renovation Cost

[severnside]

We are now at stage of agreed design with our Architect for our renovation. This project is cost bound, so we want to spend X amount of money with 20% contingency.

The design is very good and meets all our requirements. However we are not sure if this will be within our budget or not. If not then we will amend the design and it's better to

do it before planning permission.

My question is how do we get a realistic estimate before planning permission and detailed design? I have spoken to few who have recently done projects and they mentioned that

builders will only quote after detailed drawings. Architect is not fully sure if current design will be within budget. Architect also suggested that QS won't be suitable at this stage, a builder would 

provide realistic cost.

 

Thanks

[nod]

Your Architecht should be able to do a rough costing 

A better option would be to pay a building company to cost it for you 

This isnt a difficult task if you know what you want 

[Marvin]

25 minutes ago, severnside said:

My question is how do we get a realistic estimate before planning permission and detailed design?

Very difficult. But yard sticks are best. One way may be to look for 3 builders who have done similar size and type of works who you could work with and ask them for a meet or a conversation to see what they feel a sensible budget might be. 

 

Another idea is to consider where you could compromise on cost if you had to after planning and tendering.

 

Worked as a QS.

 

With no detailed design and no specification, you have no chance. Even with those, QS's best estimate, are only those. 

 

Other's more clever than me will come up with better ideas I'm sure.

 

Best of luck

 

M

[severnside]

9 hours ago, nod said:

Your Architecht should be able to do a rough costing 

One person I know ended up spending 3 times the Architects estimates. That's the reason I am being cautious as we won't be able to complete if cost go double or triple of our estimate. 

[Marvin]

If it helps, I found that the more commonplace the work the easier to cost. The more "way out" or experimental the less certainty (not that there is certainty). My experience:

 

Example 1: Full drawings, full specification, fully costed by cost engineer and evaluated by QS. Quotes came back 27% higher. Ring round for feedback: builders all very busy and would have to engage subbies and temp staff to cover work so cost higher. Market hot.

 

Example 2: Same but result 11% below: Contractor recently lost job he was hoping for and prepared to do the job at almost cost as long as it can be done before his team start the next big contract that they have 6 months down the line.

 

Two different out comes. So what was wrong with the estimate?

 

I could go on about more complicated scenarios and I'm sure other will have many fascinating examples but I hope you get my point. 

 

Finally to be 3 times over budget requires some level of unknownness (if there is such a word) : To reassure yourself, you need to analyse the reasons that happened to your friend and avoid making the same mistakes.

 

My guess would be challenges with the groundworks or changes of plans, or the other certain spanner in the works: let's get started and we'll work out how we're going to do it when we get there.

 

Good luck

 

M

[Marvin]

Forgot to say. Very good that you are considering all this now and not half way through. 

[severnside]

Thanks for the suggestions. I will try to get quotes from 2-3 builders and can pay them if required. I understand quotes will vary from builder to builder, my aim is to see what I can fit in my budget of £120K. If it's +20K I can manage but if it's £240, £300 then I will need to cancel the project.

In my friend's case they went to Architect with budget X, architect prepared a design they loved. When they went to build it costed 3X. We want to control this aspect as much as possible. 

 

I will try to calculate some work scope and post it here to do a basic check if it's realistic to expect so much work in our budget or not.

[Marvin]

Again a sensible thing to do.  Also consider any site challenges. For example access problems, parking problems.  

[Dudda]

If getting three quotes from builders at this stage definitely don't treat it like a tender and go with the lowest. At this stage you go with the average price or slightly higher to ere on the side of caution.

 

After you get planning and have the detailed drawings and specification done get a QS to do a pre-tender cost estimate. This is a great stage to change the specification of things before sending it out to tender. A good QS will be able to guild you at this stage on what parts are inflating the cost.

[Marvin]

21 minutes ago, severnside said:

I will try to get quotes from 2-3 builders and can pay them if required

 

Really I was thinking of BUDGET FIGURES.

 

I would suggest first looking for a discussion about your work and there experience with completing such a type of project.  A question I have been known to ask is :

 

"Thank for your time, I gone through some basic details with you and I wanted to know what you thought ball park figures were for this type of project. Obviously it depends on various things, but budgets for a mid range spec build, what do you think? Were talking ball park. When we come to tendering I want to make sure its within my budget and worth you quoting."

 

If you need, you could say that "the architect though it would be around the £100k touch is that realistic?

 

If your really determined, what I used to do was check planning permissions for similar work in the area of your project and find the architect/ agent on the planning application and write and ask them if they could suggest any builder to approach. Not asking for a reference! just local builders who do the same sort of work.  One question I would ask is: If it was your home is there any particular builders you would approach? 

 

and I wondered why they called me the Ferret.

 

 

 

 

[the_r_sole]

I don't understand why a qs can't do this?

We regularly have a qs prepare outline budget costs at the concept design stage - they have to make a lot of assumptions and will give a pessimistic view but at least you know if you're in the right ball park.

Builders at the moment are busy this is a time wasting exercise for them, we're struggling to get prices back for jobs which are ready to go on site, so I'd be surprised if you found any builder who's going to put time into pricing something that might never happen

[nod]

7 minutes ago, the_r_sole said:

I don't understand why a qs can't do this?

We regularly have a qs prepare outline budget costs at the concept design stage - they have to make a lot of assumptions and will give a pessimistic view but at least you know if you're in the right ball park.

Builders at the moment are busy this is a time wasting exercise for them, we're struggling to get prices back for jobs which are ready to go on site, so I'd be surprised if you found any builder who's going to put time into pricing something that might never happen

Nail on the head 

I’m pricing for work 18 months in advance 

I’m also very conscious that I may spend several days preparing a bill of quantity Only for it to be used to undercut me 

As I stated previously Approach a building company and pay them for there QS to give you a quote and a chance to bag the job further down the line 

Any free advice will be ballpark at best 

[severnside]

I did some calculations yesterday and this is scope of work we are trying to achieve. It seems our budget of 120k might not be sufficient but I am trying to understand how much it might be to see if we can stretch or change scope significantly.

Finished house will be 5 Bed, 3 toilets,1 downstairs W/C over approx 220 sq m.

Work to be done.

- Approx 16 sqm fist floor extention (above existing GF Dining Room) for a bedroom with ensuite

- Approx 45 sqm of single brick, no insulation outbuilding to be improved (insulation, damp proof) and integrated in main house

- Approx 47 sqm of new glazing

- New Kitchen/Diner with removal of internal load bearing wall

- Update 2 Toilets

- Approx 72 sqm of ground floor to change to underfloor heating and tiling

- Heating system update, currently warm air system with oil boiler (3 year old) to underfloor heating downstairs and radiators upstairs

- Whole house Rewire

- MVHR, primarily for fresh air, house might not be very airtight to get energy efficiency benefit

- Changing stairs position with  new stairs

Thanks

Edited May 7, 2021 by severnside

[Dudda]

That mightn't be enough all right. It depends on how high spec you go with the windows, kitchen, tiles, stairs, sanitary, etc. I presume they'll be decent quality triple glazed. While the extension at only 16 sqm is small it's at first floor making things more difficult and expensive than a ground floor extension. You're going to need new floor finishes throughout, repainting and if moving the stairs minor structural work and then making good and plastering all that area around the stairs as well as the wall you're removing in the kitchen / dining.

 

What work is exactly done to the ground floor? Is it just a retrofit UFH system on the existing floor with tiles on top raising the floor level circa 40mm or are you digging out the floor, adding insulation and then a new self leveling liquid screed with UFH. Massive difference in the cost between these.

[severnside]

3 minutes ago, Dudda said:

 While the extension at only 16 sqm is small it's at first floor making things more difficult and expensive than a ground floor extension.

I thought it should be cheaper than ground floor as it shouldn't need foundation, though there is risk if we need to underpin. What approx cost should I assume for such work 1500 per sqm?

4 minutes ago, Dudda said:

What work is exactly done to the ground floor? Is it just a retrofit UFH system on the existing floor with tiles on top raising the floor level circa 40mm or are you digging out the floor, adding insulation and then a new self leveling liquid screed with UFH. Massive difference in the cost between these.

It's suspended floor, so insulation between joists, spreader plates and chipboard layered with tiles

[severnside]

At this stage it would be a big help if I can get some sort of ball park figures. e.g. how much per sqm to improve an outbuilding (assume similar to garage), how much to rewire, new heating etc. If you have experience in certain area please do share some numbers. I fully understand it's difficult to estimate without full specification

 

[Olf]

Experience won't help in the current climate - I'm looking for a plumber for a full house heating + plumbing job and out of 8 local contacted only 2 found time to respond that they have books full for the foreseeable future. I assume all the others are exactly in the same position. Even one recommended by the builder (who I luckily got arranged 8 months ago) is not picking up neither mobile nor home number!

So we're really in the tough place - we can either think about a number and them make it 50% bigger to maybe 'gazump' a trade if the job is desperate, or delay some jobs until later, but face steeply rising materials costs (and labour probably too) in the meantime.

[the_r_sole]

53 minutes ago, severnside said:

I thought it should be cheaper than ground floor as it shouldn't need foundation, though there is risk if we need to underpin. What approx cost should I assume for such work 1500 per sqm?

 

Is it floating?!

If it was me I'd go back to the architect and try to get an understanding of what's actually being proposed and how practical it is  - increasing the floor height of an extension doesn't generally remove the need to build it off something and the cost of foundations for a 16m2 extension isn't likely to be a huge item so there's clearly something else at play here.

Get a QS to give you a realistic budget cost

[scottishjohn]

2 hours ago, severnside said:

I did some calculations yesterday and this is scope of work we are trying to achieve. It seems our budget of 120k might not be sufficient but I am trying to understand how much it might be to see if we can stretch or change scope significantly.

Finished house will be 5 Bed, 3 toilets,1 downstairs W/C over approx 220 sq m.

Work to be done.

- Approx 16 sqm fist floor extention (above existing GF Dining Room) for a bedroom with ensuite

- Approx 45 sqm of single brick, no insulation outbuilding to be improved (insulation, damp proof) and integrated in main house

- Approx 47 sqm of new glazing

- New Kitchen/Diner with removal of internal load bearing wall

- Update 2 Toilets

- Approx 72 sqm of ground floor to change to underfloor heating and tiling

- Heating system update, currently warm air system with oil boiler (3 year old) to underfloor heating downstairs and radiators upstairs

- Whole house Rewire

- MVHR, primarily for fresh air, house might not be very airtight to get energy efficiency benefit

- Changing stairs position with  new stairs

Thanks

If std sort of site and build --then £1800-£2500 per sq m  if you paying someone to build it for you --

[severnside]

1 hour ago, the_r_sole said:

 

Is it floating?!

If it was me I'd go back to the architect and try to get an understanding of what's actually being proposed and how practical it is  - increasing the floor height of an extension doesn't generally remove the need to build it off something and the cost of foundations for a 16m2 extension isn't likely to be a huge item so there's clearly something else at play here.

Get a QS to give you a realistic budget cost

Apologies, I should have clarified. 

- Approx 16 sqm fist floor extention (above existing GF Dining Room) for a bedroom with ensuite

 

This will not be floating, it will be on top of Dining room on Ground floor. Dining room is single storey on ground floor, rest of house is double storey. There is risk that we might need to underpin Dining room but we don't know that.

 

@Olf I understand the current situation of material and trades shortage. We are not in rush and can wait for a bit to start. At this stage I am looking to understand if it will be £100+, £200+ or £300+

[Makeitstop]

On 06/05/2021 at 10:35, the_r_sole said:

I don't understand why a qs can't do this?

We regularly have a qs prepare outline budget costs at the concept design stage - they have to make a lot of assumptions and will give a pessimistic view but at least you know if you're in the right ball park.

Builders at the moment are busy this is a time wasting exercise for them, we're struggling to get prices back for jobs which are ready to go on site, so I'd be surprised if you found any builder who's going to put time into pricing something that might never happen

 

Have to admit, I am struggling to get coatings on a job currently and it's kind of doing my nut.

 

Its approaching the point where I am considering binning the entire idea, as its aggravating even before I've got close to engaging any builder

[Adsibob]

On 05/05/2021 at 22:01, severnside said:

it's better to

do it before planning permission.

I’m going to go against the grain here and say it’s better to get planning first. You could go to all this trouble of costing a project that you never get Planning for. We thought planning would be an issue because we were doing something very similar to what our immediate neighbour had done and what many others in our street have done. We don’t live in a conservation area, yet has a real rough ride with the planners. Lost two appeals and made 4 applications in total. Eventually got something really good, but completely different to our initial design. Has we costed that initial design, it would have not been very relevant to what we’ve ended up building.

RIBA has standard guidance for costs per m2 to build different types of things, in different grades. I would use that as a starting point (I’m sure that’s what your architect has done).

 Get prices for the big ticket items like I folding/sliding doors, glazing, kitchens and appliances. Price up your bathroom suites by surveying the internet shops. 

[Adsibob]

Just a small correction to the above: we thought Planning would NOT be an issue. We were wrong.

[Ferdinand]

On 07/05/2021 at 10:22, severnside said:

I did some calculations yesterday and this is scope of work we are trying to achieve. It seems our budget of 120k might not be sufficient but I am trying to understand how much it might be to see if we can stretch or change scope significantly.

Finished house will be 5 Bed, 3 toilets,1 downstairs W/C over approx 220 sq m.

Work to be done.

- Approx 16 sqm fist floor extention (above existing GF Dining Room) for a bedroom with ensuite

- Approx 45 sqm of single brick, no insulation outbuilding to be improved (insulation, damp proof) and integrated in main house

- Approx 47 sqm of new glazing

- New Kitchen/Diner with removal of internal load bearing wall

- Update 2 Toilets

- Approx 72 sqm of ground floor to change to underfloor heating and tiling

- Heating system update, currently warm air system with oil boiler (3 year old) to underfloor heating downstairs and radiators upstairs

- Whole house Rewire

- MVHR, primarily for fresh air, house might not be very airtight to get energy efficiency benefit

- Changing stairs position with  new stairs

Thanks

 

That's a good start.

 

Also try and identify things that you could cost-control to make it a longer term project if you have real problems.

 

eg can new glazing, outbuilding, or new kitchen be treated as a later project or the kitchen done as a lower-end to be replaced after a few more years.  

[Adsibob]

On 07/05/2021 at 10:22, severnside said:

I did some calculations yesterday and this is scope of work we are trying to achieve. It seems our budget of 120k might not be sufficient but I am trying to understand how much it might be to see if we can stretch or change scope significantly.

Finished house will be 5 Bed, 3 toilets,1 downstairs W/C over approx 220 sq m.

Work to be done.

- Approx 16 sqm fist floor extention (above existing GF Dining Room) for a bedroom with ensuite

- Approx 45 sqm of single brick, no insulation outbuilding to be improved (insulation, damp proof) and integrated in main house

- Approx 47 sqm of new glazing

- New Kitchen/Diner with removal of internal load bearing wall

- Update 2 Toilets

- Approx 72 sqm of ground floor to change to underfloor heating and tiling

- Heating system update, currently warm air system with oil boiler (3 year old) to underfloor heating downstairs and radiators upstairs

- Whole house Rewire

- MVHR, primarily for fresh air, house might not be very airtight to get energy efficiency benefit

- Changing stairs position with  new stairs

Thanks

Maybe I'm looking at this with too much of a London perspective, but in London there's not a chance in hell you could do all that for £120k. But I guess it depends on spec really. E.g.:

1. What kind of glazing are you thinking of?
2. £3k kitchen or £30k kitchen?
3. Is your staircase going to be complex or bespoke? If so, you're looking at £20k plus. If you can buy off the shelf, then it's a fraction of that.
4. Will you self install the MVHR or get a professional to do it, as that could be a big saving/cost.