Structural Engineer Fees for Converting abungalow to house

gbasavar

Hi,

We are converting our bungalow into a house by adding another floor. We are also doing 2 meter side extension for ground floor. I'd hired an architect who has done a good job and she has referred this structural engineer. I got a quote from structural engineer for £2300. He gave the below proposal for the money. Can you please let me know whether it is reasonable or is he very expensive? Your help is much appreciated.

1. Design of new cut timber roof for single storey side extension. We
will assume a trussed timber roof will be used for the main roof of the
property which will be designed and detailed by the timber truss
manufacturer.

2. Design of new timber infill floors at first floor level.

3. Design of steel beams at first floor level required to support the
new timber floors.

4. Design of new lintels for the wall openings at ground and first
floor level.

5. Carry out design checks on the existing masonry walls to support
the new first floor. Opening up works will be required to be carried out by
others to confirm wall construction and condition e.g. inner leaf brick or
blockwork, cavity wall widths, condition of cavity wall ties etc.

6. Design new foundations for side extension. We will assume
traditional trench fill mass concrete foundations will be adequate for the
foundations. A tree survey will be required, to be provided by others so
that foundation depths can be determined. We would recommend soil samples
are taken to confirm the soil’s shrink ability classification. This will
need to be carried out by a specialist geotechnical engineering company.

7. Carry out design check on existing foundations. Trial holes will
need to be dug by others to survey the existing foundations. We will need
the results of this survey to carry out our foundation design checks.

8. Design new garage foundation and retaining walls.

9. Design new garage walls and roof.

10. Produce layout and details drawings for structural items 1 to 9 above.



Thanks,
G

G_M

What you are planning is an expensive conversion.

I cannot coment on the £2300, other than to say it appears reasonable given the amount of different designs he will be required to create.

Make sure you understand how much the additional investigations will cost (opening up the wall, soil sampling, tree survey, trial holes)

And of course all that is before you can get a quote for the actual construction. If, for example, the trial holes show that the existing foundations are not deep, wide, strong enough to support the extra weight of a 2nd floor, then work will be needed to strengthen/replace.

If you are still concerned about the £2300 quote, ask a 2nd/3rd structural engineer to quote for comparison.

Yu could also post on DIYNot for feedback.

gbasavar

Thanks G_M. I got couple of quotes one was quite extreme around £450! which my Architect thinks that she can't really work with them Another one is £1700 + VAT. So I'm not sure what is the reasonable price. If I read other blogs, they say around £800.

I'm trying to get few proposals for tree survey and other works.

Thanks,
G

ManofLeisure_2

Based upon my experience as an architect, I think the quote is reasonable. To be honest, I do wonder about the quote for £450, due to the amount of work involved.

Hope all goes well for you .

Nobbie1967

Have you considered just demolishing and starting from scratch? A friend of mine tried to add to a bungalow and after the investigations were complete it turned out it was going to be cheaper to demolish and start again. That was after he'd hired a massive crane to lift a portacabin into his back garden over the bungalow that he then flattened :mad:

I think you may have to do a fair bit of work on a conversion to meet the insulation regs if the original building is not well insulated. Worth considering before laying out 2k on investigations.

Mr_Costcutter

Nobbie1967 wrote: »

Have you considered just demolishing and starting from scratch? A friend of mine tried to add to a bungalow and after the investigations were complete it turned out it was going to be cheaper to demolish and start again. That was after he'd hired a massive crane to lift a portacabin into his back garden over the bungalow that he then flattened :mad:

I think you may have to do a fair bit of work on a conversion to meet the insulation regs if the original building is not well insulated. Worth considering before laying out 2k on investigations.

Goodness, unless the property is virtually derelict, why on earth would the OP wish to demolish it. Makes no sense to me.

chappers

From a builders point of view that doesn't sound unreasonable.
£450 seems ridiculously low, I pay close to that for loft conversion calcs involving no drawings.

Quick question with regards to the tree survey, has he visited site and confirmed that there are trees within close enough proximity to be influencial or has he just made an off site assumption.
Do you have trees nearby.

On the subject of insulation, if you don't remove more than 25% of the existing wall covering then there is no requirement to upgrade the insulation to that element.

As for demolition sometimes that can be the most cost effective method, no one was suggesting it was in this case, but dependent on what the SEs findings throw up it might be, underpinning the whole house in unsuitable soil for example might mean it is cheaper to start again with more suitable foundations.
If you are fit and able then digging these test holes is something you could carry out yourselves and save some cash, it just involves digging down to the base of the existing foundations, however if the upper floors structure is likely to be reliant on any internal walls for support then you may need to do this inside the house too as bungalows rarely have structurally supporting internal walls.

Has anyone else near to you carried out a similar conversion. May be worth knocking their doors and seeing if they can give you any insight as to what was involved.

teneighty

Quick response based on assumption you are in England or Wales.

Fee should be around £700 to £1000. I am working on an almost identical project at the moment and both engineer's quotes came back at around £700.

However your engineer does seem to have rather gone overboard. You do not need an engineer to "design" lintels, the architect should specify them. Likewise the trench fill foundations, should be down to the architect unless it is something complicated like a raft foundation or piling. Also timbers for roof and floors should be specified by architect unless they need to be special sizes for extra long span or unusually high loading.

Sounds like the engineer and the architect are taking you for a ride.

Mr_Costcutter

teneighty wrote: »

Sounds like the engineer and the architect are taking you for a ride.

Unless you are an architect or structural engineer, I don't think that's a fair comment as you obviously will not be certain about the amout of work involved.

chappers

teneighty wrote: »

Quick response based on assumption you are in England or Wales.

Fee should be around £700 to £1000. I am working on an almost identical project at the moment and both engineer's quotes came back at around £700.

However your engineer does seem to have rather gone overboard. You do not need an engineer to "design" lintels, the architect should specify them. Likewise the trench fill foundations, should be down to the architect unless it is something complicated like a raft foundation or piling. Also timbers for roof and floors should be specified by architect unless they need to be special sizes for extra long span or unusually high loading.

Sounds like the engineer and the architect are taking you for a ride.

That isn't how it works, the usual process is that the architect may specify suggested structural elements and put them on the drawings but building control will want those specifications approved by way of SEs calculations.
They will definitely want calcs for loading on the foundations.
You may be able to save some costs if SEs drawings aren't necessary and quite often they're not, if you engineer can liase with your builder. However for everyone involved it is better to have as much specification fully confirmed as possible before works commence.
As to what calculations the relevant BCO may want varies from individual top individual and is not something that we can speculate on here.

For the amount of work that your SE has specified I would say his fees were reasonable as to whether all that work is necessary is another matter and again not one that can be speculated upon on here.
I have done many jobs were incomplete information at the start of a project has led to many thousands of pounds of extra work.
The SEs fees are small feed compared to the overall cost of the project.

gbasavar

chappers wrote: »

From a builders point of view that doesn't sound unreasonable.
£450 seems ridiculously low, I pay close to that for loft conversion calcs involving no drawings.

Quick question with regards to the tree survey, has he visited site and confirmed that there are trees within close enough proximity to be influencial or has he just made an off site assumption.
Do you have trees nearby.

On the subject of insulation, if you don't remove more than 25% of the existing wall covering then there is no requirement to upgrade the insulation to that element.

As for demolition sometimes that can be the most cost effective method, no one was suggesting it was in this case, but dependent on what the SEs findings throw up it might be, underpinning the whole house in unsuitable soil for example might mean it is cheaper to start again with more suitable foundations.
If you are fit and able then digging these test holes is something you could carry out yourselves and save some cash, it just involves digging down to the base of the existing foundations, however if the upper floors structure is likely to be reliant on any internal walls for support then you may need to do this inside the house too as bungalows rarely have structurally supporting internal walls.

Has anyone else near to you carried out a similar conversion. May be worth knocking their doors and seeing if they can give you any insight as to what was involved.

There are no trees in my garden but small trees in neighbours garden which are bit far. So I'm not sure how they can assess it. Our Architect felt we can do it without demolition but we never know until SE verify it. I might drop the idea of doing work if I need to demolish and do it again. Already I'd a quote from one builder for around 120k.

It is the only bungalow in the street hence I can't really speak to anyone.