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Old 5th Jul 2020, 8:19 am   #21
Mike Phelan
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Default Re: Too much weight- floor collapse?

Any room for a large lockable shed?
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Old 5th Jul 2020, 8:41 am   #22
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Default Re: Too much weight- floor collapse?

What's in the room below? Could you install a couple of acrows?
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Old 5th Jul 2020, 9:13 am   #23
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Default Re: Too much weight- floor collapse?

Interesting question this. I've often wondered if I've overloaded our loft.
It's literally loaded to the rafters with kit, and I'm very reluctant to put anything else up there, but I do make sure it's all evenly spaced out and on boards to lessen the loads.
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Old 5th Jul 2020, 10:08 am   #24
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Default Re: Too much weight- floor collapse?

I think that current building regs mean you have to support a live load (that is, not the building itself) of about 150kg per m^2. It seems modern builders can meet this with 10mm thick osb 'joists' (!! really) with 40mm sq white pine flanges glued to the top and bottom, at (from memory) 300 centres. Any old house is going to be much, much better than this, unless it's utterly eaten by worm or wet / dry rot has got it. If you have not noticed your ceiling paint cracking in the room underneath, you have nothing to worry about. But if you can be a***d - measure the distance floor to cieling in the middle of the room under, with a vernier clamped onto the end of a long pole and chalk marks on floor and cieling. Now go upstairs and move all your stash into another bedroom (there's the a***d bit). Measure again. Now move it all back - measure again. Compare with Joe's suggestion above for maximum deflection over span. Deflection limits (I just looked this up as I could not remember) of span / 360 (so 3.6m deflects 10mm) used to be specified to stop you cracking your plaster underneath - but this is way short of a limit for actual structural failure.
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Old 5th Jul 2020, 10:28 am   #25
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Default Re: Too much weight- floor collapse?

Here's some tables:

http://nhbccampaigns.co.uk/landingpa...4/appendix.htm

We used similar when I was a site chippy.

Floor deflection in itself is usually no problem if you don't mind the slope, strain on the walls and ceiling boards can be another matter.

I have a wooden floor that's on 3"x2" joists that are supported every 4ft or so, it's been loaded with some serious weights since I installed it, no problems.

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Old 5th Jul 2020, 10:35 am   #26
David Simpson
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Default Re: Too much weight- floor collapse?

djmk1988, are you able to lift the carpet upstairs & possibly see if there is a plumbing/CH/Electrics access hatch, or possibly a screwed-down flooring plank which has been used when cables or pipes have been run in the past?

Also revealed should be a series of old nail heads which secure the flooring to the joists. This should tell you the approx. joist spacing. Common values from back in post-Victorian times are 16", 20" & 24". Equally important is the "Span" - distance from front to back of your house. Finally, equally important, is the size of the joists. Roughly speaking - the wider the house, the narrower the joist spacing need to be, and their size needs to be larger.

Maybe, just maybe, 3 x 9's, at 16" centres, spanning 20', could support support a fair load. 2 x6's or 2 x 7's at 24" would only support bedroom furniture. Then - is there a load-bearing wall down stairs ? Then, does the upstairs support the roofing structure via load-bearing walls?

Without pictures or structural measurements, us Forum lot are just guessing. Back in the 70's, I designed & built my own timber framed house, & still have the 3" thick TRADA design guide somewhere stored away. It contains all the relevant span tables.

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Old 5th Jul 2020, 12:58 pm   #27
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Default Re: Too much weight- floor collapse?

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Originally Posted by djmk1988 View Post
May I ask what is the possibility of the floor to collapse under this weight and should I seriously consider moving everything somewhere downstairs?
Is there scope for spreading out a bit, even a few of the heaviest items. You're obviously worried.
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Old 5th Jul 2020, 1:04 pm   #28
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Default Re: Too much weight- floor collapse?

I had 2 tons (literally) of magazines and 20 something scopes, 6 or 7 of which were 500s, an AR88 and who knows how much stuff upstairs in my old house which was a bog standard London victorian terrace. I only knew how heavy it all was when we moved. The ceiling below didn't move at all.
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Old 5th Jul 2020, 1:14 pm   #29
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Default Re: Too much weight- floor collapse?

I am just surprised that there is a century-old wooden house in central Cardiff: I never noticed any when I lived there as a student, only brick, or stone with brick corners and door/window openings. While there are plenty of centuries-old wooden buildings in Essex, Cardiff's rainfall is about 10 times greater. My understanding was that conventional wisdom is that such a wet climate is not normally considered to be suitable for timber construction. Just shows that conventional wisdom isn't infallible.

I would't worry about it. Our 1930's house had defective roof trusses that did not return the weight of the roof to the central load- bearing wall but to the middle of the 4"x2" joists spanning the upstairs rooms. This has resulted in central sagging of around 2" that was present when we moved in some 40 years ago, but the surveyors said it has gone as far as it will go so no problem. Nonetheless when we had our tiles replaced, I did have additional beams installed to return the load to the central wall, and store all my heavy stuff over the central wall.

You would clearly see signs of sagging long before a beam fractured due to excessive floor loading. The only time I have had anything go through a floorboad was as a child living in a mid-Victoran house that suffered from woodwormy floorboards. Myself and a cousin were jumping on my bed when a leg went through a wormy board. This was undoubtably due to the impulsive force concentrated on the small footprint ( less than one square inch) of the castor wheel fitted to the leg of the bed. With heavy stuff's footprint covering a wide area, the weight per square inch should't be a problem for traditional timber boards and joists.


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Old 5th Jul 2020, 1:17 pm   #30
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Default Re: Too much weight- floor collapse?

Quote:
Originally Posted by Glowing Bits! View Post
Maybe the airing cupboard door was holding up the ceiling?
Just a thought.
You're probably right! Either way, I was glad to get out of that loft!

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Old 5th Jul 2020, 1:26 pm   #31
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I saw a programme about miners, they preferred wooden props because they gave a loud creaking sound well before failure. Steel props just gave way.
 
Old 5th Jul 2020, 1:30 pm   #32
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Default Re: Too much weight- floor collapse?

Quote:
Originally Posted by bluepilot View Post
What's in the room below? Could you install a couple of acrows?
A small bar I used to go to in Bournemouth (long since closed) had two acros in the basement because the ground floor would vibrate noticeably when lots of people were dancing. Of course dancing is mostly in time so it would be more noticeable than the same number of people just walking around etc. This was 50+ people in a room not much bigger than a large lounge.

They had it checked and there were no concerns structurally with that loading, but it was a bit disconcerting feeling it and seeing movement in drinks on tables, which the acros completely eliminated.

I don't know the age of the building but it was probably 100-150 years old bearing in mind when much of Bournemouth was built.
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Old 5th Jul 2020, 1:54 pm   #33
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Default Re: Too much weight- floor collapse?

I'm an architect. I can't give you professional advice on a forum, apart from consult a professional who can inspect your house and make the necessary calculations.

Rules of thumb: As you can see from Lawrence's tables, the current building regulations have a maximum imposed load of 1.5kN/m2 which is roughly equivalent to 150kg/m2. This is to keep the maximum deflection of the beams within span (m) x 0.003. The rupture level is greatly above this. Think of how much a piece of timber can bend before actually breaking.

It's likely that the timber in an old house is of a significantly better quality than that available today. I attach a snippet from a book of a similar vintage to your house. Notice the calculation has a safety factor of seven!

Taking the modern regulations as a starting point, your equipment and you have an approximate imposed load of 0.77kN/m2. Let's assume the floor itself has a dead load of 0.5kN/m2, so the total imposed load is 1.27kN/m2. This is within the designed loading of a hideous modern rattlebox made by one of our 'housebuilders'.

However, you have no idea whether the joists are properly bedded in the wall, whether any have been flitched or otherwise repaired in the past (which could either increase or decrease load capacity), if rot is present etc. etc.

Asking on a forum is no substitute for professional advice. If you would like to engage an engineer, useful information to have to hand would be joist spacing, joist span and joist depth. These measurements will also enable you to engage in the calculations included in the snippet as they're likely what the original builders used.

In the meantime, measure the ceiling height in the room below. Check the difference in the centre and the edges. How does it compare to the modern calculation mentioned above for deflection?
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Old 5th Jul 2020, 2:01 pm   #34
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Default Re: Too much weight- floor collapse?

Quote:
small bar I used to go to in Bournemouth (long since closed) had two acros in the basement because the ground floor would vibrate noticeably when lots of people were dancing. Of course dancing is mostly in time so it would be more noticeable than the same number of people just walking around etc. This was 50+ people in a room not much bigger than a large lounge.
Natural frequency of the floor structures, student dance excitation and resonance leading to collapse of the floor:

https://youtu.be/W9e7cLCuZvc

I am surprised the neighbour downstairs was not killed or went mad with noises.

Tesla's earthquake machine is based on the same principle.
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Old 5th Jul 2020, 2:02 pm   #35
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Default Re: Too much weight- floor collapse?

Quote:
Asking on a forum is no substitute for professional advice.
Absolutely, if you are seriously concerned about this you should obtain professional advice. Comments in this thread have exactly the same status as conversations with acquaintances in the pub.

A cheaper solution would be to relocate some of the heavy stuff of course.
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Old 5th Jul 2020, 2:16 pm   #36
Uncle Bulgaria
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Default Re: Too much weight- floor collapse?

Quite so, Paul. It just always seems a little more 'weighty' when preserved in text online for an indeterminate time!

The engineer will give a free estimate, and much of the survey work can be done by the householder (especially at the moment) so the opening up to discover the joists is the most onerous part. The calculations are bread and butter so the engineer's time will be minimal. I'm trying to say that it's not an expensive endeavour, though what price peace of mind if the OP is really worried?

I spread my equipment out as it's all in use in various audio setups around the house - rather like a classic car, they last better when regularly run!
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Old 5th Jul 2020, 2:41 pm   #37
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Default Re: Too much weight- floor collapse?

Quote:
Originally Posted by regenfreak View Post
I am surprised the neighbour downstairs was not killed or went mad with noises.
There was no neighbour below, just a tiny second bar area that was never used (which is where the acros were), the beer cellar, and the toilets.
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Old 5th Jul 2020, 2:41 pm   #38
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Default Re: Too much weight- floor collapse?

Is there anything in particular that brought this concern to your mind dmjk? I'd be inclined to spread the 30 items around various parts of the house while you lift a floor board or two and check the general strength and durability of of the joists. I used to do that with a sloping floor at a previous address to make sure that the [adequately sized as it turned out] joists were not rotted or moving about in their hangers [in that case they were actually slotted into the brickwork]. Having a reasonable amount of weight placed around the perimeter can sometimes have a useful "stiffening" effect but it depends on the basic construction overall. As suggested older houses can be oversized structurally if anything but you can't rely on that. With everything out you can at least take a look and re-aquaint yourself with how the floor feels then and the difference when it's gradually loaded.

My late father-in-law was Chief Engineer at the Central Library in Manchester. He had an office down in the bowels of the building next to a huge copper rocket. It turned out to be a hot water cylinder that had previously served the entire building. Apparently the Council generated it's own electricity at one time so there was no need to worry about the "immersion" or the bill. One day he was called out advise one of the Universities which had just built a mega expensive new Library. They had a complex network of shelving designed to cover the whole first floor but could only put the books round the edges as the centre couldn't take the load. Frank was ex-Merchant Navy and not impressed by foolishness. The dismissive look on his face must have been a treat. In that sort of situation he would often deliver a sardonic "What ships have you been in?" as a stinging rebuke to those unfortunates who didn't meet his standards. I can't recall how they resolved the problem but I've a feeling that it might have been one or two steel pipes-posh acro's. The walls of the hot water cylinder were a good six inches think and when it was finally removed [in pieces] that must have been worth a lot of money!

Dave W

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Old 5th Jul 2020, 2:54 pm   #39
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Default Re: Too much weight- floor collapse?

I've seen your vast boatanchor collection Dave and on that basis I can promise djmk that he has no need to worry
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Old 5th Jul 2020, 3:19 pm   #40
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Default Re: Too much weight- floor collapse?

It baffles me why anyone would ask these types of questions on a vintage radio forum??
Why not get in contact with a local builder/surveyor, there are still some good honest ones (I know they are thin on the ground now) still around and their advice even though it might cost a few quid is far better than anyone on here who "likes to think" they know.

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