Designing my loft boarding and supporting joistwork

danlightbulb

danlightbulb

danlightbulb

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Birmingham
Hi all,

I will be be boarding out my loft for storage in the spring/summer and am planning for how I will go about doing it. It seems quite complex as there is no straightforward way to lay joists because of the arrangement of the existing supporting walls in this 1930's house which is an unusual shape.

I have created a plan of the existing framework of walls and showing how I might lay additional joists around this. I can attach ledger boards to two of the walls, the party wall at the top of the diagram, and a gable end wall on the right hand side. However on the other external walls I cannot access them because they are in the eaves.

There are three brick supporting walls that come up from the ground all the way to the loft, but they don't cover the part of the loft to the bottom left very well, and also don't cover the area around the hatch very well.

I have shown in my diagram where I might put some joists. One set on the left, spanning from the party wall ledger board to the supporting wall to the left of the loft hatch, with a bit of a cantilever to gain some extra area. One set on the right, spanning from the gable end ledger board to the supporting wall to the right of the loft hatch. And the section above the loft hatch can be filled in with some intermediate joists between ledger board, supporting wall and other joists.

But Im a bit stuck on how to complete the framing around the hatch itself and to the bottom section of the hatch where I don't have any supporting walls available unless I have some quite big cantilevers which not sure is advisable.

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dlockers said:
I'm not following - do you not have joists in the attic already?
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I need to investigate it properly but its all under insulation at the moment which needs to be moved to see what is happening properly. There are ceiling joists obviously, 2x3 I think so not big enough for properly supporting loft boarding. There will also be some purlins etc holding up the roof.

koolpc said:
Dont wait until summer as it may well be like a sauna in there at that time of the year!
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Probably spring then, I need to move insulation to do the work so don't want to do it yet.
 
danlightbulb said:
I need to investigate it properly but its all under insulation at the moment which needs to be moved to see what is happening properly. There are ceiling joists obviously, 2x3 I think so not big enough for properly supporting loft boarding. There will also be some purlins etc holding up the roof.


Probably spring then, I need to move insulation to do the work so don't want to do it yet.
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They are perfectly fine. It is a loft board not a bedroom. Run beams adjacent or use loft legs?
 
dlockers said:
They are perfectly fine. It is a loft board not a bedroom. Run beams adjacent or use loft legs?
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I want more strength than that. The floors in this house have been problematic throughout.

Even if I run additional joists along the same line as the current ones, then what do they sit on? I can't get to the eaves.

I'll grab some photos of the loft, it may help.
 
robj20 said:
I made that mistake. Best to do it in winter.
I stacked my joists to double the height, filled gaps with celotex and boarded.
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I need to redo my loft as well. I'd describe it as "partially badly boarded" currently.
How did you stack yours up? More wood, or loft legs? I thought in lofts people generally preferred to use old school fibre wool stuff and not celotex? I think the modern way of thinking is to have the insulation layer pretty damn thick right?
 
Here's some pictures but its not great because there is stuff up there currently.


Party wall looking from loft hatch. Can see the two purlins running either side.

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Left hand side looking from loft hatch.

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Right hand side of loft hatch looking down to the gable end wall. More purlins here and some ties from roof rafters to ceiling.

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Bottom left side looking from loft hatch, can't get to the eaves here. Purlins terminate into the corner supported off a large corner rafter.

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jaybee said:
I need to redo my loft as well. I'd describe it as "partially badly boarded" currently.
How did you stack yours up? More wood, or loft legs? I thought in lofts people generally preferred to use old school fibre wool stuff and not celotex? I think the modern way of thinking is to have the insulation layer pretty damn thick right?
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Already had 2x3 so got a load more 2x3 glued and screwed it ontop to give me 2x6.
Then put it 140mm celotex between and boarded.

Celotex is better bit it costs a lot more. I used it as I only needed 140mm to meet the recommended rating Vs 280mm or so if the fluffy stuff.
 
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jaybee said:
I thought in lofts people generally preferred to use old school fibre wool stuff and not celotex? I think the modern way of thinking is to have the insulation layer pretty damn thick right?
Click to expand...
270mm. The rolls come in 100 and 170mm so you can fill your joists (generally 100mm in the loft) and then do a counter flow of 170mm.
 
I think you are overthinking this - the space doesn't look particularly usable anyway, given it has those massive purlins spanning the space. The 2x3s we can assume were put in place to hold up the ceiling and have done for 100 years. It is currently used as storage/partially boarded and probably fine? No cracking in the ceiling anywhere?
 
dlockers said:
I think you are overthinking this - the space doesn't look particularly usable anyway, given it has those massive purlins spanning the space. The 2x3s we can assume were put in place to hold up the ceiling and have done for 100 years. It is currently used as storage/partially boarded and probably fine? No cracking in the ceiling anywhere?
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There's only a really tiny bit of existing boarding in the part just up from the loft hatch, only about 2x1.5m. The only other section we're using is on the left of the hatch but its just very light empty boxes mostly, nothing with any weight there. All the weight (Christmas tree, books etc) I have tried to position directly above the supporting brick wall temporarily until the boarding is sorted.

I could restrict my boarding to a smaller area but would still need to add 6" of height to take more insulation anyway. I'd rather do this with joists than loft legs. I could abandon the part which leads across to that gable end wall as those supports are somewhat in the way but I can duck under them.

And it would be good to properly board all the way around the loft hatch to make it safer to enter/exit. At the moment we can only step off the ladder in one direction because that's the only place there are any boards.
 
dlockers said:
They are perfectly fine. It is a loft board not a bedroom. Run beams adjacent or use loft legs?
Click to expand...
whose loft legs did you get ... can't see it in your thread,
after discussing with neighbour (didn't yet ask brand) they had been disappointed by the stability of their plastics so I was reluctantly considering more expensive doubling up of joists,
but the additional weight/m2 of that and the chipboard, might be approaching weight of stuff I want to move too loft,
anyway, it's the human that would be applying biggest lateral forces on the legs.
 
jpaul said:
whose loft legs did you get ... can't see it in your thread,
after discussing with neighbour (didn't yet ask brand) they had been disappointed by the stability of their plastics so I was reluctantly considering more expensive doubling up of joists,
but the additional weight/m2 of that and the chipboard, might be approaching weight of stuff I want to move too loft,
anyway, it's the human that would be applying biggest lateral forces on the legs.
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They're grand. Zero issues..the brand is literally loft legs I think. Got them from eBay. I could envisage them being unworkable with smaller 1.2x0.3boards tho.
 
I would just put loft legs in , reinstate the insulation then board over , unless you’re planning on storing a challenger tank in there it will probably be ok
 
No need to mess around then. Get new wood, lay it on top of existing wood, use structural screws and clad with OSB.

www.diynot.com

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 www.diynot.com

Diagram in post 2.

You can then clad each "join" with OSB.

---

Post 3 then says cross bracing joists is the better answer but you've already dismissed that idea.
 
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