Purlin to joist 2x1's - name and purpose?

[Twilo]

Hi all,

I have a Victorian three bed end terrace. The loft is currently being used to store junk on a few loosely placed old loft boards that will shortly be removed along with said junk. I'll then get it boarded out properly.

My question is, what are the vertical 2x1's running from the purlins to the joists for and what are they called? They're pretty flexible, so don't appear to be doing much and fixed in with a nail on either end. I can only assume that collectively they're for additional joist support to prevent bowing or something?

Only feedback I've had so far is that they might be something from the build stage and "could possibly be removed". However, the ceilings underneath are lovely and flat with no cracks so there is concern they wont stay that way if these are removed. There is a supporting wall running the width of the house through the middle.

Can these be removed?

Thanks

 

[RandomGrinch]

My question is, what are the vertical 2x1's running from the purlins to the joists for and what are they called?

They're 'hangers', they support the ceiling joists from the purlin, to help avoid sagging ceilings.

Whether you get rid of them, may depend on what size your existing ceiling joists are and what you attempt to do to strengthen them - also are your ceilings plasterboard (overboarded or not), or lath and plaster?

 

[Twilo]

Thanks for the info.

The joists are 2x3" spaced approx 21" apart. Ceilings are all plasterboard as the whole upstairs layout has been modified from the original at some point in the relatively recent past.

I would be getting a tradesperson in to do any modifications to the roof but purely out of interest, what kind of strengthening would generally be applied? Fixing secondary joists to the originals?

It's already sounding like it's not worthwhile, just for storage, but it would be nice to have the whole space opened up as I'm tall and clumsy and would probably be accessing it fairly regularly to retrieve various items.

Thanks

 

[Dereekoo]

Thanks for the info.

The joists are 2x3" spaced approx 21" apart. Ceilings are all plasterboard as the whole upstairs layout has been modified from the original at some point in the relatively recent past.

I would be getting a tradesperson in to do any modifications to the roof but purely out of interest, what kind of strengthening would generally be applied? Fixing secondary joists to the originals?

It's already sounding like it's not worthwhile, just for storage, but it would be nice to have the whole space opened up as I'm tall and clumsy and would probably be accessing it fairly regularly to retrieve various items.

Thanks

And the span from side wall to centre wall?

 

[Twilo]

12 - 13ft

 

[RandomGrinch]

The joists are 2x3" spaced approx 21"

2x3's are a little bit slim for decent storage, over that span.
But at least it's plasterboard, rather than lath and plaster that could crack, or over boarding - where the joists are already supporting extra weight.

but purely out of interest, what kind of strengthening would generally be applied? Fixing secondary joists to the originals?

It depends on what you want to achieve. If you are planning on a loft conversion at any point, you could go the whole hog and get a floor suitable for that, installing separate larger joists, maybe even steels etc.
If it's only going to be a bit of light storage, you could consider sistering some larger joists to the existing, using cross joists, or as I've done, add some reinforcement to the existing, along these lines...

Strengthening Loft floor

I am looking into having my loft converted for storage. I want the floor boarded, roof plasterboarded and loft ladder installed. The loft currently is full of a lot of boxes possibly 100kgs worth. I have had someone come round to quote for the work and they have advised me ''that...

www.diynot.com

 

[Dereekoo]

12 - 13ft

Depending whether you span 4m or 2m (with hangers) give deflection of joists 6mm or 1mm (assuming ceiling loads of 10kg/m2 and c16 wood) so defo do not remove your hangers.

 

[Twilo]

Thanks both for the prompt and helpful advice - you learn something new every day.

I won't be touching the hangers then, they are clearly integral to the structure. Regarding the storage aspect, at the moment everything is placed in the middle over the supporting wall. I wanted to expand the storage further out past the longer hangers towards the eaves. It sounds to me that I will need to have the joists reinforced to ensure no problems arise if I want to increase the floor space and access it regularly.

For anyone else reading this with little to no knowledge in this area, I just watched this great explanation on the science of floor joist spans:

It probably uses US terminology, but I found it useful and interesting nonetheless.

Thanks again for the help.

 

[Dereekoo]

Interestingly enough even with 6mm deflection on 4m span is a lot less than 1/360 so in theory your ceiling shouldn't crack, however this did not seem right and I ran the calc again and a 4m span gives a 13mm deflection which is just over 1/360. I feel better for admitting my error and just goes to show that it is always wise to check your calcs.

 

[RandomGrinch]

My ceiling joists are a similar length to the OP's and 2x3". Without hangers from the purlin, 130 years have taken their tolll, the ceilings sag!
For the lightest of storage, they have lasted, but jacking them up slightly and reinforcing them, along with adding noggins, has significantly strengthened the loft to make a really usable storage space.

 

[Twilo]

Do you think gluing and screwing 4x2's on top of the existing joists would suffice, as per this thread? Strengthening Loft floor

I'm just wanting a cost effective way for more storage and want to get a better understanding for when I get a few quotes If I'm thrown quotes for rsj's and the like that wont work for me and I'll leave it as is.

 

[RandomGrinch]

Do you think gluing and screwing 4x2's on top of the existing joists would suffice, as per this thread? Strengthening Loft floor

That's the thread I linked to earlier, it's what I've done in my own loft (similar to yours), and it worked for me.
It was a cost-effective DIY compromise, but something a trade pro may not be comfortable doing.
Get a few quotes and see what is offered!

 

[Twilo]

Yeah that's why I referenced it, thanks for the link - I've saved the sketch tony1851 posted. If I'm honest I'm quite happy to do that myself, I just need to clear it all out first and take up the old insulation to see what I'm dealing with in full. Not looking forward to that bit as it's like a Saharan sandstorm up there as a chimney stack was taken out years ago and everything you can imagine is still circling around up there. Henry the vacuum to the rescue!

Thanks again for the help. Might post back when it's done...

 

[RandomGrinch]

I just need to clear it all out first and take up the old insulation to see what I'm dealing with in full

Yes, I did the same, new insulation and an industrial vac.
A disposable suit, goggles and a comfortable (valved) ffp3 face mask are worth using.
Which means, don't leave this work till summer - spring time, with a little more warmth up there will be ideal.
Good luck and please let us know how it goes.

Edit, just to add I used some decent length coach bolts and washers to join the joists.
Checking measurements first, I pre-drilled the holes and clearance holes through the new joists downstairs, before taken them up.
The turbo coach bolts went straight in securely with little effort and no splits.

https://www.screwfix.com/p/turbocoach-hex-flange-coach-screws-m6-x-100mm-100-pack/8226g

 

[Dereekoo]

Tony's method is as good a monolithic 7 x 2 joist as you are going to get with out actually using a new joist, you will recall from your youtube video that the neutral axis is in the centre of the beam meaning no stresses and whilst your joint is not in the exact centre it is not far out and friction/compression stresses in that area will be small compared with the outer faces.
Running the calcs (hopefully with no mistakes) in theory with a 7 x 2 beam you can actually load the beams so the floor is imposing a load of 150kg/m2 (as opposed to just the ceiling load of 10kg/m2) and the deflection would be in line with what it is now i.e.<1mm but I would suggest improving the single nail fixing of the hangers