Questions about a loft conversion

[LeeDowner]

I'm just starting to think about getting my loft converted, I haven't contacted the council or any builders yet, I'd just like a few questions answered before taking that next step.

First I have these brick and wood roof supports which would need to move somehow because they take up too much space. The house was built circa 1901 according to the survey we had when buying so most internal walls are brick, should mean the supports have other places they could be moved to ? I uploaded pictures but can't figure out how to get them into this post, they are in my album though if anyone cares too look.

The ceiling joists are only 2" x 3.5" but there are a couple of much larger joists that run the entire width of the loft space that stand on top of the smaller ceiling joists. What are those for ?



Thanks

 

[skhudy]

the architect / structural engineer will spec up some steel beams to replace those supports to your roof, so they will go

 

[skhudy]

mistake post

 

[freddiemercurystwin]

Typically two steel beams are slung from party wall to party wall at the front and back, then a structural timber stud wall is built up to the underside of your lower purlin and then the rafters can be strengthened and the upper purlins removed. Then a new timber joist floor can be supported between the two steel beams. That little lot will open up your loft space.

The biggest headache in small houses is fitting a new stair access in and the headroom both for the stair up into the loft and usable headroom within the converted loft as valuable space at floor and roof level will be eaten up by additional structure. If you have an existing open plan layout on the ground floor this can be problematic with respect to fire escape.

Forget about the joists sitting on top of your existing ceiling joists they are not doing anything structural.

You don’t need an architect or a civil engineer, you need an architectural technician.

A Full Plans Application is prudent and ensures you ~(or your builder) knows exactly what to do throughout the build and he doesn’t have to make it up as he goes along. I would be looking for a good set of plans, a detailed section or two and some proper details of the various junctions like how the floor is supported off the new steels, how is the dormer constructed etc etc.

Loft conversion Procedure goes something like this:

1. Unless you're willing to mess about with the layout on paper and learn about the relevant Regs then approach an Architectural Technician (see Yell or speak with friends or family for recommendation’s) not an Architect. No need to bother with a SE just yet though they will be required later on. Invite 3 Arch tech's round to have a look and give you a quote go with the one you think is best. You can also check out your Local Authority online planning register to see who the popular technicians are.
2. They will have a look and give you your free hour or so and hopefully give a rough idea that installing a staircase is feasible or not (presumably as similar houses to you have done lofty’s it will be. Explain you want a proper set of working drawings and not just a plan and generic section with a load of notes. Ask to see a typical loft conversion set of working drawings when he pops along to see you.
3. If it is feasible then give you a quote (probably somewhere around £500-800) and confirm to you how much the local authority fee will be (probably around £500) and how much the structural engineers fees would be (probably around £100-400).
4. If you are happy with his quote he will then do a survey.
5. Then he will produce some existing plans and a section or two.
6. Then he will produce some proposed floor plans showing you a workable layout or two (assuming a workable layout can be found). He should include a rough section to show how much usable headroom you will have. He should take into account the additional structure and insulation required.
7. Then if you are happy he will do the detailed drawings, including a couple of details showing the important junctions and at this stage he will be talking with a structural engineer to confirm steel beam sizes etc.
8. Then he should send you the completed drawings ready for your approval.
9. Then he submits them to building control for approval.
10. These drawings can then be used to get accurate quotes for the work and can form the basis of the contract with your chosen builder.
11. Then you can start work using his drawings.

 

[freddiemercurystwin]

Untitled

• LeeDowner
• 20 Nov 2014
• 1

Untitled

• LeeDowner
• 20 Nov 2014
• 1

 

[tony1851]

Plenty of headroom up there, and a good steep roof - ideal for a loft conversion.

(If I'm not mistaken, that wall supporting the purlin is 9" brickwork - that house must have some good thick walls downstairs).

 

[LeeDowner]

Thanks for the detailed reply Freddie.

Is there any way to get a conversion signed off without a staircase? I was only thinking of a loft hatch and ladder. It would be used as a room and not just for storage though.

Also I'd like to do some aspects of the conversion myself including the electrics, would that be a problem with the council? I would extend the upstairs ring to the loft to provide power and lighting is there already. All steel work and joist work, fitting velux window, reinforcing the roof etc would be my builders job.

Thanks.

 

[tony1851]

FMT is the resident loft expert here but FWIW may I put in my 2-cent's worth?

I think you'll find that Building Control won't entertain the job if you just have a loft ladder but want it for 'more than storage'; they will regard it as a habitable room, so the full gamut of regs will kick in.

Doubt you can do the electrics yourself unless you are Part P registered?

The steel beams and roof structural alterations cannot just be 'left to the builder' - B.C. will insist on structural calcs being submitted, and you will need to engage a SE to provide those.

Best get someone to draw proper plans (as above don't even think of engaging an RIBA - a good tech will be as good if not better) and do a proper Full Plans building regs application.

 

[freddiemercurystwin]

You can have a fixed ladder (ie permanent ships ladder) if the loft only has one habitable room and if there is not enough room for a normal stair without having to alter the layout, or a space-saver of course. But the point is they need to be permanent (and rightly so IMO).

http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_K_2013.pdf is your friend 1.29-1.31

I think you can certainly do some if not all the electrics yourself, I posted a while back what can be done without BC approval I think, (I might have a gander for it). What needs approval would need BC to inspect and I suspect may charge extra separately (I think but am not sure) or get it inspected and signed off by a {Part P approved) electrician I think. Gah! Electrics really ain't my bag!

 

[LeeDowner]

A permanent ladder would interfere with landing space so maybe a hatch isn't an option.

Are steels always necessary? I only want a velux flat window if that makes a difference. Couldn't I have the new joists running from party wall to gable end wall supported on joist hangers? My gable wall goes from floor outside straight upto the apex of the roof so there's two solid brick walls opposite eachother in my loft space.

How're the rafters reinforced if the upper purlins and supports are removed?

Thanks for the help, I like going into these things armed with the right information.

 

[freddiemercurystwin]

Generally you can run joists from PW-PW but generally the span will dictate timbers that if used will be more expensive than a couple of steels and smaller timbers spanning between them.

If some of the internal walls are structural it may be acceptable to bear onto these, thus shortening the spans a making timber sizes more reasonable.

Rafters are reinforced by bolting an additional rafter to them if necessary. It may not be necessary.

There a few ways to approach lofty's but too little information provided thus far to provide any definitive or recommended approaches.

Find a good technician and he will explore and talk you through all this!

 

[Cabbyfan]

Re electrics, I am renovating a property at the moment including sorting out the existing horrible loft conversion.

Soon as I got the keys I got BC over and got him to confirm a yes or no to their need for sign off on certain jobs. Electrics can be done so long as you can present a final inspection and test cert by an approved person or company. In my case I have specified a local electrical contractor will inspect and test but I a doing the install of all circuits and consumer unit. What you can't do is rewire yourself and get a random part P person to just sign it off.