Hello, i am working on plans for my loft conversion. i have had the drawings done and now i think i will need to have some structural calculations done. does anyone know any independant engineers in north yorkshire.

i have had a quote from a company and it is £700 inc vat to do the calcs, and drawings etc.

i really think this is excessive and only want to know the answer to a couple of questions.

1) can i run the joists from the spine wall of the house into the gable walls. This spine wall has a 9x2 joist sitting on it which forms a triangle in the centre of the roof which is part of the king beam holding up the roof.

essentially i will be hanging my new floor off this joist. This way of spanning the joists is the shortest and most simple.

i have a few other questions, but this is the main stumbling block.

Posted By: marsaday£700 inc vat to do the calcs, and drawings etc.

'fraid not. your paying for the structural design; the drawings and calcs are generally free...

Posted By: marsadaythis is excessive

£610+VAT not bad, at the top end maybe but not necessarily, 'pends how complicated it is and how good an engineer they are... how much would you spend paying a mechanic to rebuild you car... lawyer, accountant... surgeon...?

Posted By: marsaday1) can i run the joists from the spine wall of the house into the gable walls. This spine wall has a 9x2 joist sitting on it which forms a triangle in the centre of the roof which is part of the king beam holding up the roof.

couldn't tell with out survey drawings and calcs... ...that's why you need an engineer...



J

James, have to disagree. I designed my floor layout in my loft without a stuctural engineer. I've also designed many others. Depends on several factors but mostly

1. Will any bearings safely transmit floor loads to the ground?[which can often be dealt with by digging a trial pit]
2. Whether something outside of domestic span tables is required ie. Steel. If spans are less than 5.2m [from memory] timber sizes can be taken from TRADA span tables. If not TRADA, then the old Part A.

Posted By: Mike GeorgeI designed my floor layout in my loft without a stuctural engineer

What did you charge yourself?

"1. Does the spine wall go all the way to the ground and is it sat on a loadbearing foundation?
2. What is the span between the spine wall and the external walls which will presumably form the other bearing for your floor joists?"


ok, some more info for you all:

Of all the lofts to convert this is the easiest to do, gable walls, no roof dormers, big space, lots of head room. 1910 house in red brick. All internal walls are ground based. the house was built on a brick rubble base, but not sure what the foundations actually are. the ground floor is all concrete, except the front room which is joisted. So i am pretty sure this is a strong old house. the egineer has said not to worry about the foundations as he thinks they will be fine.

the spine wall is 6.3m in length and the joist which sits on it is 8.5m in length. The last 2.2m has no support as the front room opens out to the side here. i understand here i will put in a steel and run the joists from this into the front wall. this area is also where the stairs come up.

i have photos, put not sure how to post here.

the joist spans laying this way will be 3m and 3.5m

i will try and post this drawing i have done, but not sure it will post.

space isnt a problem, so i will be floating well above the ceiling joists

Work out your own solution, then double the size of all structural members. It'll still be cheaper than hiring a structural engineer.

i have a solution and can go the long way from front to back, but i will still need to take some loading off the spine wall.

So all i want to ask is can this wall take some loadings or all loadings ? I am not paying £700 to have that answered. if the structural engineer on here thinks that is a reasonable price then i give up.

i will be getting an engineer. just one who charges a reasonable price.

i have given the design drawing to them to photo copy, so yes they have these.

I myself had a figure of £400. They charge £50 an hour and i reckon 8h's coming to measure and then do the workings etc is a reasonable time frame.

i will try another company.

I did a loft conversion for a customer (storage not living space) removing trusses to enable space to be used. I did drawings for the customer but explained that as I was not a structural engineer I would have to get one to do the "sums" for me to prove to L.A. it would take the loads. I intended to make two structural beams consisting of top and bottom purlin with vertical and diagonal timbers. I have done this many times on other jobs and had no problems. The customer had a relation who was a structural engineer and wanted to use him for the calcs. What I got back from him was nothing like I had proposed but two glue-lam beams (top and bottom) with ply glued and screwed to one face. The problem was the beams were 8mtres long and each beam was 340mm by 150mm. I priced the beams and indicated to the custmer the price would go up by £1000 just to buy the beams. Also because they were 8metres long we could not get them in in one piece (houses either side were in the way) they had to be joined with engineered plates.

The structural engineer even added a beam in the ridge (240mm by 120mm). I have only ever had to place additional beams in the ridge if one slope of the house is being replaced by flat roof dormer or tile loadings changed on one elevation. The L.A. inspector said this was not required but was included in the calcs.

Even the L.A. inspector said the glue-lams were completely over the top but said he was in no position to argue with the calcs. The customer went with this design purely because blood is thicker than water, but it cost him dearly ( and they were a bugger to get up in the loft).

If I was younger I would love to go to night school and learn how to do these kinds of calcs. I, like most builders with a good reputation, know what will stay up and what will fall down but get fed up with some architects who re-design your proposal because they think they know best. This does not mean that I am not open to suggestions from qualified people as we never stop learning.

End of rant

Remember your not just paying for their expert knowledge on structures but also the assurance that if does go Pete Tong you can go back to them with a legal foot to stand on. Remember if it was easy everyone would be doing it.

Nice brickwork evident in the background. Round or arched window going in there perhaps?

Posted By: DAI_EVANSthat if does go Pete Tong

Do you think the aforementioned disc spinner ever says, 'its all gone a bit me'...?

J