# Forum Home Renovation Structural Renovation  Very wide span tables

## RumpledElf

Another thread probably talking myself out of even considering this church. This is a job for a structural engineer, of course. 
Googling and searching here the only thing I can find that can span 8m clear (no supports except each end) for a mezzanine floor are floor trusses. And of course there are no indications of what such things cost. I couldn't find information on laminated beams, probably using the wrong search terms. 
I'm figuring that to do this, you'd need to run an extremely large beam of some sort along the walls - probably a 290x45 or larger, or steel - stuck on with REALLY big dynabolts, and then use joist hangers off those to put in a mezzanine. I can't see using joist hangers directly onto a stone wall being a particularly safe option - although Grand Designs did it, of course. 
This is a really, really horrifically expensive notion, isn't it ...

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## SilentButDeadly

Go to the Carter Holt Harvey and/or Dindas websites and look for 'Hyspan' and 'Hybeam'...these things will generally only go no more than six metres in single lengths but if you double them up it'll win...expect at least $30 per metre for Hyspan though 
Hopley's steel trusses are another alternative.  
One of the dudes profiled on Grand Designs built an entire free standing frame inside the stone church....

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## RumpledElf

Cheers for that, more to search for. 
I have friends in a church conversion and they've randomly stuck steel I-beams to the walls everywhere and attached ordinary verandah posts wily-nily directly to the floors. Its ugly and probably downright dangerous, these people wouldn't know a span table if it sat on them. 
Their main bedroom is a platform with two kid's bedrooms under it, just stud pine sitting on the floor, unlined, exposed wiring, absolute monstrosity. They have an enormous and quite ornate Catholic church too, the abomination of a 'conversion' they have would make most of the people on Grand Designs run away going 'la la la' with their hands over their ears. All Jarrah floors too, chipped to all hell and unpolished. 
My old house is ex-commerical and has beams spanning 10m in the ceiling - solid hardwood, several inches thick. Impressive stuff. The verticals in there are foot-square hardwood posts.

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## cherub65

Hynebeam will span 8.0 m 360 x 65

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## Pulse

Having trouble picturing the plan. Do you want joists that span 8m or bearers that span 8m. 
A few options: 
1. plywood box beam- just had a look, they can span up to 7600 as a bearer with a FLW of 3000 for the joists. This is for a 1200mm deep box which would make a good mezzanine railing, just would need a stairwell inside the mezzanine area. 
2. Lite steel Beam - the largest 300x75x3mm spans 8000m as a joist at 450 centres, spans about 6800 as a bearer. 
3. put in a post near one end to reduce the span. 
4. use the floor truss 
Cheers
Pulse

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## Pulse

Just another point, 8m is way to far for an average joist to span no matter what material, most of the time concrete would be used in heavy construction or trusses for roofs and the like. Best to spend some decent cash on a bearer or steel beam on the free edge of the mezzanine and buy cheap joists for the short span. 
Chemical anchors with threaded rob would be the best way to attach massive loads into old masonry 
Pulse

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## Stan 101

A Pryda Longreach floor truss will span 8000mm at 450 crs.
It is 500mm deep. You might prefer to close up the spacings to 300mm crs. Here's a quick design. 5mm deflection @ 450mm crs. Allow about $45 - $55 m2 for floor trusses at 450 crs.   
The Hyspan is an option but they will be very expensive.  
cheers,

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## RumpledElf

> Having trouble picturing the plan. Do you want joists that span 8m or bearers that span 8m.

  Two MASSIVE stone walls, approx 8m apart. Bridging the gap and putting a mezzanine on there - the mezzanine itself would be only 4m wide or so so in theory,  three massive bearers would do it, that gets ~2m spacing for the joists so you could use regular stuff from there up. Or just 10 of those floor trusses at 450 centers. The building being what it is, exposed wood bearers of some sort would look the prettiest, but floor trusses look the cheapest/most practical. 
This is certainly all food for thought and obviously not a DIY job - I need to stick my nose into the council planning department and see what they have to say about this. And pray that bloody REA actually gets my house sold so I have a  snowball's chance of *buying* this thing.

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## brissyboy

At a guess from your description your floor load width is 2m (half of 4m). Below is very rough without seeing the job but  
Steel wise roughly you could use:
Universal Beam UB310 32  cost about $76m unprimed
PFC 300 $93m unprimed. 
Anyway possible that you could run a bearer the other way and split it into 2lots of 4m then you have a lot more options. A 200mm square post or in your area you might be able to find an old round post from a barn or something similiar that would polish up well

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## RumpledElf

A post would eliminate a lot of issues dropping the span from that unmanageable 8m down to a nice 'small' 4m. 
The floor in there is old Baltic - there's no way you could just lean it on the floor (although I know people who have done this in the same situation  :Eek:  ), you'd have to get it down to ground level somehow, and I can't think offhand how you'd dig footings under a floor without having to take up half the floor. You can't get heavy machinery in there so it would have to be hand-dug the old fashioned way. We took up old, really crap baltic floors here (1900 house not a 1875 one) and when they came up they split and broke all over the place, so they don't handle being moved well. 
Meanwhile I'm STILL waiting on a verbal 'offer' on the place, and a possible purchaser of my old house (also a high ceilinged 1870s sandstone ex-commercial building) - can't have one without the other. Country real estates are a slow, laid back bunch.

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## brissyboy

Hi R E 
I assume that there is a crawlspace underneath. You do not need to actually to cut through the floor. You would rest the post on top of the floor ontop of a joist where it sits on the bearer. You would then get into the crawlspace and put a 75x75x4 steel post (or you could make a masonry support) directly under the bearer that is under the joist where the timber post is sitting on the floor. IF you are getting soil testing for another purpose then get the engineer to design the footing depth otherwise 600mm would do it at a guess or if you hit solid rock you have gone far enough. (though do restump buildings this way and sometime3s even have to dig crawl channels through so they can pull the concrete bucket through and as it is only one stump a bit of effort but would save you a fortune). This way the bearer and joist would not actually be deemed to be carrying any load as the load is transferred through the steel post and into the ground.
BB

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## Cooky

I reckon don't bother with putting in extra posts. For the money and time required, just put that into bigger main beams.  
An important point if you're gonna follow regulations, is that a mezzanine floor must be designed for LL=3.0 kPa. If you want it for the standard residential load of 1.5 kPa, you can't call it a mezzanine. If it's storage, then LL is even more.  
So still going with the mezz loadings, there's no chance that standard joists will span 8000 or the main beams be timber.  
By necessity main beams are steel - use a PFC cos one side is flat so looks better on the outside, and by aesthetics it seems solid timber preffered for joists: 
250PFC (92% loaded) each side, pack them out and stick in 240x45 F17 joists at 450 CTS (limited by deflection). 
Someone said chemical anchoring is best for masonry - his head is screwed on. 
A double check that the strip footings can take the existing loads plus the new floor loads would be needed. 
At some stage, if you need official designing and certifying for this, let me know. 
Cheers

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## Cooky

What about your stairs going up to the floor? The type of stair and where you put it may have an influence? They'll also put extra loads onto the main beams.

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## NigeC

I wouldn't dynabolt to the wall. Go for an independant steel structure, that way you know it will handle all the weight you will put up there. Engineered of course, It is cheaper to engineer this kind of structure than calculating wall/span loads. It just so happens that UB's come in 8 metre lengths 
Installation would be the tricky part, probably scissor lift to lift the beams in place while ladders to put bolts in (construction grade bolts of course). Steel posts will have base plates and all-threaded into ground with chemset. Depending on quality of footing you may need to put in plinths which aren't crazy expensive for what you are talking about, and will come with the hold down points as part of the plinth 
With an independant steel frame your joists can be the normal 450 wide and walls where ever you want them. Services onto this structure is easy (power, gas) Stairway can be self supporting or engineered into the design (spiral, what ever). Steel structure can be boxed in with any kind of material you desire (timber, masonry, glass etc)
The kids can sleep safe underneath know that mummy and daddy and 3 tonne of structure/bed/ fridge/plasma and 10 tonne of wall/steeple/leadlight window is not going to come down on them!
Church conversions are great, good luck to you if you have a go at one, at least you can see where your friends went wrong.

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## RumpledElf

Well, at the moment the other half is vehemently against buying ANY other house (our current house is a very small 3br cottage with only one living area and we need to squeeze 5 people into it soon) let alone a church conversion - despite the possibilities to make it into a bloody enormous house ... 
So I think this is going to be moot and we're going to be sardining for a while yet  :Frown:  
Unless that church is still for sale in a year, anyway.

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## NigeC

What a shame, this would have been a great build to watch. Surely would have ended in divorce though!

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## Smac

Was looking for similar things myself and found a very helpful document from a steel fabricator in NSW, it gives you all the spans and applications for said spans and what spacings and sizes.  It is all available from OneSteel you just call a supplier and get a price on the product number
Hope this is of help
PS if you want the official spans for timber let me know as I have the framing books with tables

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## Bloss

Pity - churches make very good houses especially  with a mezzanine - I've done two in my years with my Dah and both were very special places. Not cheap but OK if an OK DIYer. And LVL beams can be most lengths - just that the standard sizes around 7-8m for issues of transport. Of course once you order special price goes up, but plenty of engineers will show you how to compound them to create longer spans.

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