Floor strength for heavy(ish) machinery

[MikeG.]

I always double up joists under bath locations, and specify a load-spreader on the floor under the feet to relieve the point load. The thing with baths is that they generally stand fairly close to a wall, and bathrooms are generally small rooms, and thus the span is generally small. That's quite a different thing to standing a piece of equipment in the middle of a floor which was under-specced to start with. Filing cabinets are the other one to watch out for: paper is damned heavy. The only total floor failure I've ever seen was because of a row of filing cabinets.

 

[Blackswanwood]

Sounds risky. https://www.ehow.co.uk/how_7485788_calc ... acity.html may help or confuse further! I would want a structural engineer to opine.

 

[MikeG.]

........ https://www.ehow.co.uk/how_7485788_calc ... acity.html may help or confuse further! .........

Confuse, definitely. That again is dealing with a uniformly distributed load, not a point load.

 

[dizjasta]

This thread has been interesting and informative, it seems your workshop was erected some time ago and may have been constructed to regulations that prevailed at the time. Is this the case? Present day tables for beam sizes and spans for domestic applications will provide advice for the designer to provide a safe structural member which also avoids cosmetic upset due to deflection that may affect plaster decoration.
I doubt your workshop needs decoration. On the information to hand It seems the first floor was intended for storage at around 40lb/ft2* and allowed pedestrian access for up to 4 people.
I think further examination of the flooring strength is needed. I believe that your floor will take your equipment and 2 people but no storage.
It is estimated that your first floor space has an area of 330ft2* supported by 14 joists that will have full loading with the 2 joists at either end being ignored. What is the first floor size?

 

[MikeG.]

This thread has been interesting and informative, it seems your workshop was erected some time ago and may have been constructed to regulations that prevailed at the time. Is this the case? Present day tables for beam sizes and spans for domestic applications will provide advice for the designer to provide a safe structural member which also avoids cosmetic upset due to deflection that may affect plaster decoration.
I doubt your workshop needs decoration. On the information to hand It seems the first floor was intended for storage at around 40lb/ft2* and allowed pedestrian access for up to 4 people.
I think further examination of the flooring strength is needed. I believe that your floor will take your equipment and 2 people but no storage.
It is estimated that your first floor space has an area of 330ft2* supported by 14 joists that will have full loading with the 2 joists at either end being ignored. What is the first floor size?

All of which suggest you too are treated this as a uniform load, not a point load.

 

[sammy.se]

What is a cross beam ( I don't know the right term) was placed above and perpendicular to the joists, and the joists then attached to them?

I know it sounds a bit crazy, and introduces a massive trip hazard... But...

I only suggest this because in my Victorian house loft, there is a 3x8 beam across the 2x4 ceiling joists at the mid point, supported by the brick walls, and the joists are attached to it. Presumably to prevent sagging. The total span is about 5 meters.

I know, not ideal, but maybe this might make it possible?

Sent from my Nexus 5X using Tapatalk

 

[MikeG.]

Underneath is the obvious answer.

 

[sammy.se]

Underneath is the obvious answer.

Even better.

OP - why not just add a beam below?

Sent from my Nexus 5X using Tapatalk

 

[dizjasta]

This thread has been interesting and informative, it seems your workshop was erected some time ago and may have been constructed to regulations that prevailed at the time. Is this the case? Present day tables for beam sizes and spans for domestic applications will provide advice for the designer to provide a safe structural member which also avoids cosmetic upset due to deflection that may affect plaster decoration.
I doubt your workshop needs decoration. On the information to hand It seems the first floor was intended for storage at around 40lb/ft2* and allowed pedestrian access for up to 4 people.
I think further examination of the flooring strength is needed. I believe that your floor will take your equipment and 2 people but no storage.
It is estimated that your first floor space has an area of 330ft2* supported by 14 joists that will have full loading with the 2 joists at either end being ignored. What is the first floor size?

All of which suggest you too are treated this as a uniform load, not a point load.

Mike my comments are directed to the original poster to garner information. No mention of "uniform load".

 

[dizjasta]

This thread has been interesting and informative, it seems your workshop was erected some time ago and may have been constructed to regulations that prevailed at the time. Is this the case? Present day tables for beam sizes and spans for domestic applications will provide advice for the designer to provide a safe structural member which also avoids cosmetic upset due to deflection that may affect plaster decoration.
I doubt your workshop needs decoration. On the information to hand It seems the first floor was intended for storage at around 40lb/ft2* and allowed pedestrian access for up to 4 people.
I think further examination of the flooring strength is needed. I believe that your floor will take your equipment and 2 people but no storage.
It is estimated that your first floor space has an area of 330ft2* supported by 14 joists that will have full loading with the 2 joists at either end being ignored. What is the first floor size?

NickM do you have any details to hand so this matter can proceed or perhaps DEVELOPE!!!!!!!

 

[deema]

I would listen very carefully to Mike. An architects opinion on such things is not something I would ignore.

The old rule of thumb for floor joists was to half the span and for every foot use 1” of thickness plus an inch. Interestingly your joists should only have been used to span 14’ using this rule.

As a slight aside, I understand building regs were first started in 1965. I’d appreciate knowing from Mike if modern regulations apply to old floors built before this time or do they have grandfather rights?

 

[NickM]

Unfortunately I don’t think a beam underneath is possible (or at least would be too big a job).

I wanted to use the space above the garage, because I thought it would be fun to embark on a new hobby making sawdust upstairs, whilst carrying on with one of my other pastimes of tinkering with a car I built a few years ago downstairs.

However, taking account of the helpful comments here, I think I am going to move to plan B which is to set up ‘shop in an old stable building. There is some negotiating to be done as I may need to turf out some of my wife’s bee keeping kit and some camping gear, but that’s all light so should be safe above the garage. In reality, I think the stable will actually be a better space. For a start it’s full height and it’s on the ground! I’m fortunate to have an alternative.

So, I’ve got a few things to organise, but I think I can start looking around for some machines again!

Thanks again.

 

[MikeG.]

Now you're talking! Let's see a photo or two of this old stable..........

 

[MikeG.]

The old rule of thumb for floor joists was to half the span and for every foot use 1” of thickness plus an inch. Interestingly your joists should only have been used to span 14’ using this rule.

Plus 2", and you never go far wrong. That rule only applies to 2" wide joists, though, and his are 3".

As a slight aside, I understand building regs were first started in 1965. I’d appreciate knowing from Mike if modern regulations apply to old floors built before this time or do they have grandfather rights?

Building regs only apply to stuff to which new works are done. Old stuff benefits from the principle of "at least as good as it was before" if it is rebuilt/fixed up but falls below the threshold of being controllable. So, as long as no work is done to old floors, building regs are irrelevant (unless stipulated by, say, an insurance company or a mortgage provider).

 

[NickM]

Now you're talking! Let's see a photo or two of this old stable..........

I’ll try to do that!

The garage has a bit of history. I think back in the day it would have housed a proper vintage car (would have been state of the art then of course). It used to have a pair of sliding doors - the tracks are visible in the floor. There’s even an old petrol pump and, I assume, there must be a tank underground somewhere.

Unfortunately a beech tree fell on it about 15-20 years ago and pretty much destroyed it. The previous owner of the house was in the garage with his son when it came down - the tree was already listing severely and they were trying to rescue his Triumph TR6! It was probably the heavy cast iron petrol pump which saved them as it stopped the tree getting right down to floor level. They rebuilt it and took the chance to add the upstairs room.

 

[deema]

Thanks Mike, really appreciate it.

 

[NickM]

Partly as a test to see if I can upload photos, here is a shot of the stables in the snow. The stables are either side of the stable door - you can only see one side (with the arched window).

 

[NickM]

The picture upload worked!

Here is a picture of the inside of one of the stables with the current “horse” - my dad’s old Wrigley truck which spent a good twenty years in daily use in his greenhouses in Guernsey before he retired from growing flowers. It now gets a bit of use shifting stuff around my garden (when I can get it to start...).

The stables are smaller than ideal but I think I’ll start in one side and gradually move into the other as I subtly move my wife’s bee keeping stuff out...

The “chocolate bar” floor is going to be a bit of a challenge in terms of getting machines/benches level, but I’ll find a way to overcome that.

 

[MikeG.]

Brilliant. That should make a wonderful workshop. Get some more photos when you can, and we'll see the size of the task. It might be worth leveling the floor before moving anything into there.

 

[NickM]

And finally, here’s a picture of the petrol pump in the garage which I mentioned in a previous post (sorry, it’s on its side).