Boarded victorian loft weight

[BenTenBox]

Morning.

My wife and I have moved into a victorian semi detached house. Our loft was already boarded when we moved in and I wondered what it was Ok to store up there as I know they were not built to take weight. I've attached a few pictures but the roof is of Purlin construction and the joists/rafters are 2inch by 4 inch and spaced a foot apart and the chipboard that was laid is almost an inch thick. As we've just moved in I've put some boxes up there but nothing that heavy, things like sailing jackets, camping bits like a tent and sleeping bags, and we've got some old clothes and pans. I've not got any stacked book boxes or anything.

My question was really does this seem like a reasonable weight considering the structure?

[tabbypurr]

you gave us 3 dimensions but not the 4th - joist length.

NT

[Tim Watts]

Jesus, yes. That exceeds the way most houses are made now...

4x2" is good. The spacing is good. Likely the victorian lumber is superior to anything sold for that purpose now.

The only factor you haven't stated is the span of the joists.

Mine span 3.5m and are 2x4" of 1950s grade timber. All 100+kg of me can stand on a single one mid span with no flexing.

The worst I've seen is in my childhood house - same, 1930s timber. One ceiling dropped by an inch off the roof tie above it - that was due to a shedload of books being piled in a cupboard mid span - a very bad placement of load.

So:

1) You have spread the load;

2) You won't break the joists - you'll cause ceiling cracks before bad things happen;

3) If you keep the load fairly well distributed you should be able to store a reasonable amount of stuff - especially if you keep heavier things nearer the suppporting walls.

[GB]

Whilst the timbers can take considerable loads for a while, they may distort slowly from long-term loads (like the books you mentioned), leading to a bowed or cracked ceiling.

I don't think the one inch chipboard increases the strength - it just adds to the load!

[Tim Watts]

No - but it does spread any point loads over several joists.

Our loft was fantastically overloaded in a small area (because only a bit was boarded with simple planks).

[Andrew]

15 mm OSB is far lighter and just as strong when screwed to all the joists.

Downside is you cannot add more loft insulation.

I overlaid the trusses in my 1976 semi with 50x50mm timber 3.6 metres long at right angles to the trusses and raised up with sections of 18mm ply about 12 inches long and 6 inches wide. These are glued and bolted vertically and have a 2x2 slot at the top end which carries the lateral 2x2 timbers which are about

600 mm apart carrying 15mm MDF sheets that were 600 by 600 mm and discarded from a b&Q refit at 50p a sheet.

The 6 inch gap between the tops of the trusses and underside of the MDF is filled with extra rockwool, running the same way as the added

50x50 timbers.

[harry]

You can strengthen is significantly by screwing a "joist" on top of the floor, at right angles to existing joists and right underneath the purlin. Then put in hangers between this new joist and the purins

[BenTenBox]

replying to harry, BenTenBox wrote: many thanks for all the replies, I'll measure the joist length when I get home, there are several walls directly below, the main wall running along the middle of the top floor, presumably I should measure from that wall the end eaves?

additionally, if I want to keep the current contents there, should I add hangers and a new joist?

[John Rumm]

Yup, the longest unsupported span...

If you concentrates heavier loads over the wall below you will also reduce the possibility of further sagging (a small amount is inevitable, and you don't usually even see it from the room below).

Unless you are going to go mad with storing heavy stuff, I would not bother... (I would also be wary of transferring too much new floor load to the purlin, since that has a roof load to carry anyway).

[Bob Eager]

Make sure the walls are all supporting walls.

[BenTenBox]

replying to Bob Eager, BenTenBox wrote: Sorry for the dumb question but how do I tell?

[Brian Gaff]

Yes agreed about the ceiling. Its actually often worse if you put a bookshelf on the upper floor of the house and the downstairs ceiling bows! Brian

[newshound]

My first (late victorian) house had been boarded to make a maid's room. IME even these joists will be bigger than typical living room joists in a modern house.

[tabbypurr]

Wood bends a long way before it breaks, if you overload it you'll get ceiling plaster cracking & sagging. When it's sagged 6" or a foot or so it might then snap.

NT

[BenTenBox]

replying to BenTenBox, BenTenBox wrote: Ok, well, I've tried to figure out which is the load bearing wall, we have two upstairs one that runs front to back but is not mirrored downstairs, and one that runs side to side, halfway down the length of the house, this runs both upstairs and downstairs. This also has one of the purlin supports fixed into it. Assuming then the beams are unsupported from there to the eaves the joist length would be 4.1 metres unsupported, the photo attached has my finger pointing to the support thst I think goes to the supporting wall, and the rest of the photo shows the length of unsupported joist, this is assuming that the very large beam in the photo is not supporting them. If it is then the unsupported length there is 2.1 metres .

Does that make any sense?

[BenTenBox]

replying to BenTenBox, BenTenBox wrote: Ok, so having done more reading to reduce my ignorance, the span either side of the binder in the previous photo is 2.1 metres.

Also, is it better to place load near the party wall?

[harry]

Additionally. If the joists are at right angles to the walls beneath, the walls offer support.

If they are parallel the don't.

Same goes for party wall. They are usually parallel to party walls

[harry]

Timber and steel beams in constructions work are sized to avoid deflection under load which would cause cracks to appear in cement/plaster/tiles etc.

They are thus well over sized as regards load carrying ability.

[Martin Brown]

Mine is built to an earlier grade of Victorian engineering and the beams are roughly 3x10" pitch pine and at 18" spacing with floorboards in the loft as well as on the suspended floors. I doubt there would be any practical way of overloading it short of storing gold bullion up there.

My first home built in the 1970's the loft timber could barely support the roof and you needed to be very careful not to put anything heavy up there or to stumble in the loft for fear of cracking the ceiling below.

It would creak as you shifted your weight on the boarded section.

+1

Worth looking to see if there are any load bearing internal walls too.

[BenTenBox]

replying to harry, BenTenBox wrote: I guess that my concern was that I've heard horror stories about storing items in Victorian lofts and didn't want to fall foul of it and check the strength before overloading it