I'm considering installing a beam and block floor in Nassau but...

[Boyblue]

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.  

Edited Monday at 12:37 by Boyblue

[Conor]

Why do you want to use block and beam? What's the usual local way of doing it? Doing something different to what is typically done, will inevitably be more problematic, time consuming and expensive.

[Boyblue]

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? 

Edited Monday at 13:00 by Boyblue

[Conor]

What are you building, what stage are you at, what are you comparing your B&B pricing to?

[Mike]

2 hours ago, Boyblue said:

we're running out of fill (to bad we can't use sand)

Wouldn't it be cheaper to import fill (hardcore or insulation sheets) rather than beams?

 

2 hours ago, Boyblue said:

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?

I'm not clear which dimension are which, but you'll need a design from the beam manufacturer, so ask them. But placing beams closer isn't an issue by itself.

[Boyblue]

4 hours ago, Conor said:

What are you building, what stage are you at, what are you comparing your B&B pricing to?

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 

Edited Monday at 17:58 by Boyblue

[Boyblue]

2 hours ago, Mike said:

Wouldn't it be cheaper to import fill (hardcore or insulation sheets) rather than beams?

I'm not clear which dimension are which, but you'll need a design from the beam manufacturer, so ask them. But placing beams closer isn't an issue by itself.

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.

[Boyblue]

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?

[Mike]

1 hour ago, Boyblue said:

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

8mm isn't that much - if you apply the grout with a screed rail over the top it should level it up - I'd be surprised of the beam manufacturer would have a problem with that.

 

[Mike]

11 hours ago, Boyblue said:

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 dissipate?

If you have radon you'll need a fully sealed radon barrier over the top of the beam & block floor and across the walls (before you build them up), then a screed to protect it. You'll need to adequately ventilate the void below.

 

BTW, if you're installing aircon, then it would be wise to make sure that the building (above the radon barrier) is airtight, to keep the warm air out & the cool air in.

 

 

[Boyblue]

2 hours ago, Mike said:

8mm isn't that much - if you apply the grout with a screed rail over the top it should level it up - I'd be surprised of the beam manufacturer would have a problem with that.

 

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.                                                                                                                                                                                                                                  

Edited yesterday at 02:20 by Boyblue