Loft

[ghannath]

Hi.

After a bit of advice and some opinions on my loft. I live in a victorian house which has a good sized loft with no structural obstructions. The loft already has a Velux and is already boarded out onto the original floor joists which are 75x50 (3"x2") and 300mm apart. I want to tidy it up into a proper room just for storage and hobbies (scalextric for the kids and some music stuff. Do I need to reinforce the floor to do this? The dimensions are roughly 5m x 10m with the main interior wall of the house running down the centre so the span of the joists is 5m from the outside walls. Then there's two purlins on each side with a gap of 3.5m from eachother.

Any advise would be appreciated, thanks.

ghannath

 

[Chukka63]

yep,you'll need all new joists approx 9x2.So manypeople think a boarded out loft is a good start,like the people im converting their loft at the mo but it just increases the cost when it all has to come out.

many threads on here covering this.

 

[PrenticeBoyofDerry]

It depends which way you go about it.
The official line would be to have it accessed by an engineer or architect for it being structurally sound, as most lofts are designed to take light storage. This doesn't mean that yours will need extra support though.
If this room was to become a permanent one, consideration for staircase, door, fire prevention and alarm, windows, electrics, etc.. would need to be taken, and this will involve using building controls and complying to the relevant regulations.

 

[ghannath]

Hi

I've had it looked at by a builder I know and they say it's structurally ok. 9x2 joists seem a little overkill for a storage room although I appreciate your opinion, it would also impact on head height quite a bit. Would a new set of 4 x 2 joists hung between the Purlins do the trick for the floor area? This would be a span of 3.5m with the middle internal wall being half way along. This means the joists would be supported by the Purlins and the middle internal wall. The room will never be a permanent room, it's not big enough and there's no room for stairs.

Thanks again in advance.

Regards
ghannath

 

[Framer]

Hi

I've had it looked at by a builder I know and they say it's structurally ok. 9x2 joists seem a little overkill for a storage room although I appreciate your opinion, it would also impact on head height quite a bit. Would a new set of 4 x 2 joists hung between the Purlins do the trick for the floor area? This would be a span of 3.5m with the middle internal wall being half way along. This means the joists would be supported by the Purlins and the middle internal wall. The room will never be a permanent room, it's not big enough and there's no room for stairs.

Thanks again in advance.

Regards
ghannath

your existing perlins will be spec'ed to carry the roof load so you should not add extra load to them without calculations from a structural engineer

if you have a span off 1.75m ( half the 3.5m as you have a wall to carry them) you could use 97 x 47 c16 so the solution would be to install ub's under the perlins and hang from these, but again you will need SE calculations.

 

[ghannath]

Hi.

Sorry, maybe I'm using the wrong language;

I have two Purlins on each side of the pitched roof holding up the rafters at around 1/3 and 2/3 up. Then there's two of the same sized beams across the floor from the outside wall to the supporting walls underneath. Are these ones across the floor called 'Purlins' or something else? They are 9x3 and are the ones at 3.5m apart with the central internal wall half way between. These are the ones I'm on about hanging the joists from to make a false raised floor.

By the way, what are ub's?

Thanks for all your help.

Regards
ghannath

 

[ghannath]

Hi

Ok, after an extensive look around on here I think I'm referring to 'binders' not 'purlins'. So, I have two 'Binders' at 3.5m apart with a structural wall at midpoint. Can I hang joists off these binders, spanning and using the internal wall to create my floor for storage etc?

I know what you're gonna say; 'talk to an SE', but I want an idea before spending that money, thanks.

ghannath

 

[DevilDamo]

Speak to a few SE's and get a few quotes and then take it from there.

The majority of SE's I've worked with will come out for an initial site visit/discussion with no fee but they would obviously be limited as to how much information they can or will provide just incase you go about it yourself based on their advice or approach somebody else.

 

[Deluks]

Hi

Ok, after an extensive look around on here I think I'm referring to 'binders' not 'purlins'. So, I have two 'Binders' at 3.5m apart with a structural wall at midpoint. Can I hang joists off these binders, spanning and using the internal wall to create my floor for storage etc?

I know what you're gonna say; 'talk to an SE', but I want an idea before spending that money, thanks.

ghannath

Firstly, well done for answering your own question via the search facility.
Secondly, No. Binders are in effect holding up the joists (although that is not their sole function) So any weight added will increase the chances of the deflecting, possible outcome: bowed ceilings beneath.

By the sounds of things your binders are larger than normal, but then your joists are smaller than normal so I'm guessing its to compensate for the shallow 3" joists. For example, my house is 4x2 everything, except for 3 chunky purlins.

UB = Universal beam AKA an RSJ

I would suggest as a 'posh loft' solution you'll end up having to fix deeper joists to the side of the existing as previously stated. Have you looked into the idea of a proper conversion?

 

[ghannath]

Hi

Thanks for that. I have looked at a 'proper' conversion but it's just too pricey for the usage it'll get. Having said that I'm not going to go ahead with the cheapy route if it means my house will fall over! I've read some posts on here where people are planning scary stuff to get as cheap as possible with no regard for regs or physics.

If I attach 4" or 5" joists to the existing ones are you talking all the way across the house or just in the centre where I'm planning on having the floor? Also the binders are above the joists, does that mean the joists are just nailed to the underside of the binders?

Thanks.
ghannath

 

[Deluks]

You should ideally be going between 2 load bearing points, ie: a wall beneath or a hanger attached to a gable or side wall.

The binders will get in the way though and these should not be taken out willy-nilly. If you butt new timbers upto the binders they will still be able to deflect, if they so wish.

Middle ground would be to lose the binders and sister the joists with some 9x2 or 8x3's including strutting. However you won't able to remove any of the other timbers holding the roof up.

Without getting a loft conversion proper, you could get advice from an SE on how to make the floor suitable for one (conversion) and just get that done without stairs, velux etc. So a conversion would be possible in the future without redoing the floor. Bit of a grey area though.

The current binders/ceiling joists will be nailed at an angle and are a strong enough connection for the intended purpose.

 

[ghannath]

Hi

Thanks for all the info. I'm gonna get someone in for a look and will post the results here if I go ahead.

Cheers
ghannath

 

[ghannath]

Hi

Ok, someone's had a look and advised that removing the binders and attaching larger joists to the existing ones would be the best way to go. This would mean that the new joists would span 4.5m each between the outside wall and middle internal wall as the current ones stop just over the internal wall. To do this I need to remove the binders which will no longer be necessary.

So...How do you remove the binders??? It seems a bit chicken and egg. Apparently the ceilings and existing joists are in good nick and there's minimal or no sag currently. Surely without anything in the loft the joists can hold their own whilst the binders are removed shortly before adding the new ones. My main concern though is how to physically remove the binders. They'll need to be cut into sections to remove them from the loft, can this be done in situe and removed in bits?

Any advice greatly appreciated as usual although I'm beginning to think that I'd be better getting the floor done professionally and doing the rest myself.

Thanks
ghannath

 

[Deluks]

Tread carefully, do one at a time working from the outside inwards. Cut a space for the new joist, insert joist, fix. Onto the next one. A reciprocating saw with a demolition blade suitable for nailed timber is good for this.
Not strictly necessary but for peace of mind some acros fitted underneath with a scaff board under/over with a dustsheet protecting ceilings/floor. Don't go mad tight, just a snug fit so they can't fall over.

Who did you get to have a look and what size timber did they recommend?