Can a rafter and purlin rooflight loft conversion be completed without any steel in the floor?

Paddyone

Please can anyone advise? 
Can a rafter and purlin roof light loft conversion be completed without any steel in the floor? This is a prewar property with a loadbearing wall under the apex. I intend to eventually apply officially but just want to be prepared. 
Thank you for your time.

Paddyone

Also, Would you use a loft company or steer clear as this seems to be the genuine rule of thumb today or would you use an architect stroke structural engineer to do the plan on paper and PDF format to email out to hundreds and gain quotes from individual qualified contractors?
Thank you again.  

FreeBear

If it is anything like my pre-war home - The majority of the timbers up there are 3"x2" - Over a 3-4m span, no where near strong enough for a floor.

Do it right. Get proper plans drawn up, structural engineer calculations, and steels where required. It will improve the saleability of your property when the time comes if you have the correct paperwork in place.

DOH_a

When you say ‘within the floor’, do you actually mean ‘within’ or are you really asking if a conversion can be done without the need for any steelwork?

For your typical loft conversion, an engineer would design a steel to sit above the existing ceiling joists and then hang the new floor joists off that steel. So that steel wouldn’t be within but above the ceiling. In addition to that, you’d normally expect double/triple timbers to form the new stair opening as well as any other trimming/support requirements. These joists are normally positioned within the ceiling. As a result of the above, there will be disruption to the existing ceiling in one way or another.

If however you are asking if you need any steel beams at all, that would depend on the loadings and what an engineer can do to distribute them. Engineers would sometimes design a steel at the ridge or a fitch beam.

Andy_L

Depends if the existing joists are up to it or not.

Paddyone

DOH.a
The question should have been, can a skylight conversion be done without the need for any steelwork? 

We have started a Roof light or Sky Light conversion ( no ensuite) as we were advised that this is by far the cheapest and least disruptive option, as we won't have changes to the shape or pitch of the roof.

Rightly or wrongly, we have deviated from the outdated 'Full Plans Application Dormer Loft Conversion with Ensuite' due to a change in our circumstances. We have had a full reroof, skylight windows and insulation added. Then later we had a floor layed due to the old Victorian ceiling joists and Lathe not being fit for the new purpose. New full-length timber joists were added and run from the back to the front of the property and rest on a loadbearing wall that is centred in the room. I recall the joiner needed to avoid the spars so the centres are different (he provided a paper drawing for future use). I believe the use of the loadbearing wall cancelled the need for steel which is stated in the original submitted plan. All the ceilings below have been boarded and skimmed to current building regulations.

We have enough ceiling height for a staircase to make the room habitable. We assume that the expense of finishing the room will be lost if we cannot gain a completion certificate and this would cause holdups should we sell in the future. I also worry that the LA can enforce us to complete or undo the completed work. Are these assumptions and worries correct?

If enforced the insulation would not meet current legislation and if enforced would lower the ceiling height which would prevent us from fitting the stairs to building standard regulations. However, I researched insulation and it appears to state that if the upgrade is not technically or functionally feasible then it can be upgraded to the best possible standard and a payback of no greater than 15 years can be followed to achieve it. Is this correct according to UK legislation?

Thank you. 

rach_k

It sounds like you need to get a structural engineer to have a look at what the joiner actually did (hopefully the drawings are accurate and detailed enough for this) and then make the calculations.  I don't think there is any way you can get a proper answer on here because you need measurements to work it out, plus I doubt many people would even know where to start!  When we had our loft conversion done, there was a load bearing wall under the centre of the loft but we still needed steels.  The roof went on last, so it sounds like you have done yours backwards.

We used a building and carpentry company with a lot of experience in lofts, so not really a 'loft company'.  They sorted out getting the plans drawn up by an architect and dealt with building control etc.

DOH_a

Paddyone said:

DOH.a
The question should have been, can a skylight conversion be done without the need for any steelwork? 

Or put correctly... a loft conversion incorporating a rooflight. You wouldn’t call a garage conversion a window conversion 🤪