t-beam flooring query

MPA

We have a 15 yr old bungalow which is constructed on a t-beam and block system. We recently had to open up part of the floor when replacing a bathroom suite and we discovered that there is a 6 foot drop below the floor into water. Am I right in assuming this under-floor area should have been filled up to just below the level of the t-beam and block flooring (or at least to a height which is close to the ground level outside)? I am also worried that this has huge potential to be a radon trap. Any advice? If this is not a good situation, is there an easy way to correct it without having to lift floors everywhere?

reilig

MPA wrote: »

We have a 15 yr old bungalow which is constructed on a t-beam and block system. We recently had to open up part of the floor when replacing a bathroom suite and we discovered that there is a 6 foot drop below the floor into water. Am I right in assuming this under-floor area should have been filled up to just below the level of the t-beam and block flooring (or at least to a height which is close to the ground level outside)? I am also worried that this has huge potential to be a radon trap. Any advice? If this is not a good situation, is there an easy way to correct it without having to lift floors everywhere?

I have been doing some research on t-beams in the last few weeks as I am using them to construct a balcony on my new build, so from what I understand about them after talking to suppliers of them, they are designed to act in the same way as hollowcore flooring. ie, you do not need to fill underneath them. My blocklayers told me that they have seen many house floors constructed with t-beams which saved a lot of fill in the floor and they wondered why I wasn't going for this system in my new build (to be honest, I only found out about t-beams after I had the floor filled).

Finally, I don't know too much about radon barrier and t-beams - maybe it was put in on top of the t-beams and blocks and then the floor poured on top of it?? Perhaps the best way to ease your mind about radon would be to have it tested by a radon testing company.

Regards

Dan

MPA

Thanks, Dan. That is reassuring!

Michael

topcatcbr

The void under the floor should act like a large radon sump. if this is ventilated it would disperse any radon safely into the athmosphere. nothing makes this type of construction worse than the alternitave traditional ground supported floor slab. on the contarary it should be better in terms of radon.

Slig

The main reason for using a suspended ground floor is if the level of fill exceeds 800mm. As stated above this void should act as a sump. if you are worried then provide ventilation to it by fitting a vent on either side or pipe to eaves and fit mech extractor as with a standard sump

MrLNB

might be a bit off the current topic. But i am thinking of using T-Beams on the first floor of a two story rather than slabs,

Pros & Cons of each if you can,

I think T-Beams are far cheaper than slabs,

also access to the site for slabs might be a problem.


Lnb

topcatcbr

the first concern for me would be the fixing of a ceiling. This is not as straight forward for t beams though not impossible.

L driver

Hi,
This is an old thread, but just wondering has anyone experience of using beam and block instead of hollow core? Have read about using HD eps or aircrete blocks instead of concrete blocks. I'd say the lip of the t could be drilled for fixing of a suspended ceiling, as have seen done with the lip at the edge of hollow core. Just seems there could be a saving over hcore, financially not including ones labour.

sydthebeat

L driver wrote: »

Hi,
Have read about using HD eps or aircrete blocks instead of concrete blocks.

is this a ground floor or intermediate floor?

L driver wrote: »

Hi,
Just seems there could be a saving over hcore, financially not including ones labour.

current wideslab prices are extremely competitive (in the region of €30-35 per sq m installed). i cant see how much saving can be made as there is still the inherent costs of getting the beams to site and using crane to install.

L driver

Syd,
Intermediate/first floor, google throws up plenty of manufacturers. Would think this should decrease the 'heat sink' associated with concrete hcore? I dont see the need for a crane if one had their own digger or one hired on site. I'm just curious is it a good alternative, once it is designed by a suitable person ie t beams closer when carrying 1st floor walls, as many builders have the time to put in the blocks themselves now and of course using less concrete in the build.

sydthebeat

L driver wrote: »

Syd,
Intermediate/first floor, google throws up plenty of manufacturers. Would think this should decrease the 'heat sink' associated with concrete hcore? I dont see the need for a crane if one had their own digger or one hired on site. I'm just curious is it a good alternative, once it is designed by a suitable person ie t beams closer when carrying 1st floor walls, as many builders have the time to put in the blocks themselves now and of course using less concrete in the build.

"heat sink" to one is a "thermal store" to another......
personally i think the focus should be on thermally massive elements as stores and not sinks.

T beams were more common when hollowcore was an expensive option used more for commercial builds. Nowadays with the advent of a commonly used wideslab, t beams are used less frequently. They are generally used in ground floors where there is a build up of hardcore so deep as to render a poured slab unacceptable.

morning delight

sydthebeat wrote: »

T beams were more common when hollowcore was an expensive option used more for commercial builds. Nowadays with the advent of a commonly used wideslab, t beams are used less frequently.

Is wideslab different to hollowcore?

sydthebeat

morning delight wrote: »

Is wideslab different to hollowcore?

only in that 'hollowcore' has exactly that, hollow cores within the slab
http://www.ipcprecast.com/IpcPrecastPortalContent/Image/Products/hollowcore.png

'wideslab' is a whole unadulterated slab of reinforced concrete.
http://www.moyleengineering.com/Images/products/flooringbeds2400-5.jpg

crossmolinalad

someone knows wher i can get those ones here in Ireland Only ones i can find are concrete blocks
Blocks u see on the pic are been used in almost whole of europe and the only thing u need is a screed floor on it
Those blocks have a radon barrier and are isulating

morning delight

sydthebeat wrote: »

only in that 'hollowcore' has exactly that, hollow cores within the slab
http://www.ipcprecast.com/IpcPrecastPortalContent/Image/Products/hollowcore.png

'wideslab' is a whole unadulterated slab of reinforced concrete.
http://www.moyleengineering.com/Images/products/flooringbeds2400-5.jpg

Thanks syd,
I thought that was the case but asked just to be sure to be sure!;) Good pictures by the way.
So what are the advantages/ disadvantages of either one over the other? As a 1st floor the main criteria I can think of off the top of my head are: cost, noise, thickness, width that can be spanned. I'm sure there's more...