Floor loft and remove central joists

[Deleted User]

Hello!

I live in a terraced house with a small loft, around 30m sq - the middle section has already been floored but I've been looking to floor the other 2/3rds. I've had a quote of £800 to do this:

- floor 2/3rds of the loft
- remove 10 diagonal joists (pieces of wood going from the floor to the centre of the triangular roof) and replace them with horizontal ceiling joists

The builder also said that I do not need to get drawings or a structural engineer out for this, even though he plans to remove the central joists (he says is a joiner with a nvq and 'city and guilds' qualifications).

Is this fair, and more importantly, safe?

Thanks!

Deleted_User

phill99

The fact that you are posting on here suggests you have doubts. The only people to answer your question fully are Building Control. Call them in the morning and explain the position. Then you'll know the definitive answer.

julianashcroft

You don't need to get a Structural engineer out before he does the work, but you may regret it afterwards. The timbers that are in there haven't been put in for looks but for a structural purpose. I would be very wary of anyone who says they can just take something out without doing proper checks.

[Deleted User]

thanks guys! that makes a lot of sense. i've looked around more as well and found out that my roof is supported by:

'Pre-Formed Truss Rafter' system. This is a method of supporting a tiled roof where there are no interior brick or block walls to put the load of the roof on. The system works well until the wooden trusses are cut through and they lose their strength. Skilled experts can overcome and adjust the structure so this loss of strength will be avoided and your loft can still be converted.

that's from a website selling trussed roof loft conversions, but even with a pinch of salt removing those trusses does seem risky!

phew! saved my life, nearly went for that!!

julianashcroft

If It's a trussed roof, then cutting bits away without an engineers involvement would most likely result in most of the roof making an appearance into the bedrooms below.

thebaldwindowfitter

it sounds like you are talking about diagonal bracing and your builder is going to fit horizontal instead .the bracing is their for a reason and is fitted after the trusses are erected to give strength to the trusses .As i understand this he is taking the diagonal bracing off so you can gain access to the space behind and board the top of the ceiling joists can i ask if there is diagonal bracing to the underneath of what i would call the roof joist . I personally if this was my house would say that if the roof had diagonal bracing (to roof joists)as described earlier and horizontal braces were put in on the roof joist and were the triangle is formed in the area of those you are taking out this should be more than adequate your flooring both what you are doing and what has been done previous should be fine providing the walls underneath can take the extra weight

[Deleted User]

thanks! i have another question about how much _just_ flooring should cost, will put it up as a separate post

leveller2911

Deleted_User wrote: »

Hello!




- remove 10 diagonal joists (pieces of wood going from the floor to the centre of the triangular roof) and replace them with horizontal ceiling joists

The builder also said that I do not need to get drawings or a structural engineer out for this, even though he plans to remove the central joists (he says is a joiner with a nvq and 'city and guilds' qualifications).

Is this fair, and more importantly, safe?


It looks like your "builder" is intending to cut out the "Wind braces" on your trussed roof and fit ceiling collars. A trussed roof is designed to take the weight of the roof tiles,stand up to high winds and take the weight of all the odds and sods we all store up there. What your "builder" is suggesting is a not safe and not correct.All trussed roofs and designed to take huge loadings in certain areas and are all certified to meet standards.

The minute he cuts out a brace and fits a collar he will void any Public Liability insurance he holds and when the roof collapses he/you legally won't have a leg to stand on.

Just to add don't take too much notice of his NVQ as this counts for nothing with regards to structural engineering.You can qualify for an NVQ level 1 having studied for 1 day a week for 12 months.

Any alterations to a trussed roof should always be checked before work is started by a qualified Structural engineer.

[Deleted User]

thanks leveller2911