Boyblue

100mm solid blocks are not available here so I've been looking at importing the beams and using hollow (three hole) blocks. One of the first companies I looked at had the 3.6n category. Now that I'm trying to choose from the available options, I notice there aren't many. I'm concerned about being in the minority here. Are hollow blocks less than ideal, inefficient or ineffective?

That must have been some span, did you use standard beams or 215 beams?

As you say, this has to be well thought out during design, but can be done even with blocks. If blocks of the right height can't be bought, they can be cut. If there is a section of a foundation that needs 215mm beams,then the rest has to be worked out. I'm guessing that the designer would spec out the rest of the job with 215mm beams unless there was a huge cost savings, inclusive of the needed modifications.

On one hand I can see where engineered bricks could make up for the height difference, on the other hand if you're expecting the slab to become a monolith upon completion, the different size supporting members must make sor some messy calculations for the designer. Then again maybe not, because each section is supported seperately. I thought about the additional cost of the additional course of bricks but there is no additional course because the 225mm beam section would actually carry one less course, support would only be needed for the 155mm beams. I can see hoe the split installation would work ok when building with brick but I can't see it working as smoothly when working with block foundations. Am I missing something here?

It was because I liked the idea of having manageable lengths plus, I had an issue sourcing a crane that didn't include excess charges. But you've now introduced a new dynamic. In a situation where the technology is new to folks here, bouncing floors would be a nonstarter, so if we need to include additional support, it will have to be done. Whether by installing a sleeper wall or a pier with a beam I’ll let the engineer decide the most economical solution.

I'm good with using a crane because I beleive the long spans end up being more economical and I didn't have an issue hiring a crane, my issue was the minimum rental time. It wasn't looking good for a minute, I kid you not. All inclusive of riding time, the first company minumum 3 hours, second 4 hour minimum, third company one day minimum. That's when I started to purchase 🙂But through contacts I've been able to get the minimum reduced to two hours and I'm comfrotable with that.

I notice that your foundations have lots of interior walls that make beam and block installation easier, we don't have that. Good point

As mentioned I haven't seen how the girders are used in conjunction with beam & block, and I'd be curious as to how it works. The drawing is just a sketch, no engineering involved. Let's presume the girder is properly sized and attached, the purpose would be to support beams and block that would run perpendicular to the girder. So that instead of 250kg, 6.85m beams you'd have mor managable 4.36m beams to install. Maybe it's because all the homes here are built slab on gade, but most plans have few internal foundation walls, so opting for Beam & block could add significant cost. I was just thinking that in a case where the plans have already been approved, having an engineer add the girder detail would be a simple fix, that is if they are designed for that purpose. Of course the simplest thing to do would be to add the middle wall to the foundation design.

I've seen mention of girders as part of beam and block but I can't find a video or pictures showing how it's done. Is a girder able to span 6m and carry the weight of all the beams that would be resting on it?

So the options are to build more internal walls to keep the spans to a managable length or rent a crane. manpower against the price of crane rental. About how long would it take to place beams on a 100 m2 foundation, give or take?

Thanks Mike, I prefer to stay away from uncommon solotions, I'll have to ask the engineer to inclide the 50mm screed in the calculation.

Thank you that is helpful info. Based on your experience what's the longest span would you suggest be done manually and I'm wondering that for as long as the Brits have been doing beam & block why aren't there buggys or trollys made for moving beams?

Thanks, I read that you can do a 25mm screed if you use bonder, is this something that is common? Would you advise this?

Great point, particularly beacuse my blocks are 43 mm smaller which brings the beams closer, so the addition would be inconsequential. The chart below indicates no screed is necessary but I'd feel comfortable putting 50mm on there. We're adding cost but considering the fact that I won't have to import blocks, it's a cheap out.

They don't sell or use beam and block! They went another direction, engineered lumber and wood are their materials of choice. With that combination they get pretty firm floors, so much so that they can probably pour concrete on that base if they want to.

Any specific one? It's guava season, maybe that's it?

LOL, I wouldn't say it's overated, but I wish we had seasons.

Those are the two styles to which I was refering. It may be an efficiency thing, less material means less weight and less cost, right

First sizable hiccup, in checking the measurements of the local block, 3 5/8" comes to 92, so the beams are going to be much higher than the blocks. Anyone know if there is a beam that has a top section less the 100m?

It's not just the fill, steel is ultra expensive as well, I mentioned that in my answer to the previous post. Thanks for the direction, Once I've chosen a manufacturer I do as you suggest.

Vacation homes and we're at the stage where we've chosen a site. That drawing details in the original post tells most of the story. Two facts left ot are that the finished floor must be 610mm above street level and the footing must be in 155mm of rock. In the normal course we're talking 3 - 5 course of block which would be $1,200 - $1,500 per unit but this site has a parcipitous dropoff and to fill each unit will cost $6,000. Plans call for 4 ground floor units. Then there's the point that with a suspended floor we may be able to use that space. For an interior suspended floor we generally use steel web joists, which indicates that it's probably cheaper than a reinforced slab. One web joist for a 6m span would likely be around $2,500. I priced one for something like a 4.5m span last month and that was $1,950. I estimate I'm trying to beat 60k

Is there a difference between the straight T beam and the one that looks like a capital I with nods at the top that almost mirror the bottom? Is it just a style thing or are there critical differences that should be considered when selecting? Are there less consequential differences like might one or the other fit more snugly or require more screed material? Is one more popular, or more commonly used? When no screed is detailed on a beam span chart, does it mean that a screed is unnecessary, or is it that none can/should be applied?

There are two answers, for the ground floor, we're running out of fill (to bad we can't use sand), I'm still running the numbers but I anticipate some savings. If I'm wrong, I may still do it because it's something that we will have to come to in a few years and I like trying new things when building. For the upper floor it will definitely be less expensive, one bar joist for a 4.5m span is $1950. I haven't started that analysis yet but the installation should be similar, correct?

I'm considering installing a beam and block floor in Nassau, Bahamas but the only current option is to import the beams from your side of the pond. The issues are that the local block is 7mm shorter and 43mm narrower. I'm not too worried about the height as the slurry will take care of that, but should I worry about the beams being 43mm closer? Importing the blocks would make the whole thing less feasable. Another other Issue I'm having is collecting technical data from company sites. I'll need to have a local engeneer certify my plans and do the beam layout. I anticipate that his questions will very specific. Will suppliers have a problem with sharing this information? The last big one (for now) is that I would rather not put any vents in the foundation. You will see from the attached foundation detail that dampness is not an issue for us, a 3mil vapor barrier is placed under the concrete slab and that's about it. I plan to cover the ground with a vapor barrier but not tape it so that if moisture does get in it can drain out, your thoughts? As far as Radon, our houses are not air tight, so if radon comes up shouldn't it dissapate? Of course the engineers will have the final say once plans are submitted, but I'd like to submit a plan that's solid because every inquiry from them is a delay, so I would appreciate any input.

Believe it or not, you guys are the world's foremost experts on beam and block Floors ; at least the english speaking world, and I'd like to learn more about it, so I'm here in hopes of learning a bit, confirming what I have learnt and, possibly adapting some of your methods to fit our environment. I was general contractor a couple lifetimes ago, so I may be able to help now and then with some issues. I guess we'll have to see.