# should we go for concrete or joist 1st floor?



## nina

Hi, I'm hoping for advice as looked through but can't see any at the minute. My husband and I are building and wondering should we put in precast concrete floor upstairs. We think it would be worth it for soundproofing. His dad says that we should just double joist the upstairs and that that would be fine and a lot cheaper. We want to put in wooden floors upstairs. Has anyone experience of either (good or bad) that they could share? It would be much appreciated.


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## Carpenter

If you intend to have underfloor heating in the house it might be worth considering a lightweight concrete screed (50- 75mm thick only) on insulation, ply and timber joists.  This offers many advantages over a standard timber floor: underfloor heating capability with rapid response time, not overly expensive when compared with a precast concrete slab and good acoustic performance.  This option also allows you to run services (plumbing/ electrics etc) through the joists as in a regular timber floor construction.  When precast flooring is used you must of necessity batten out the underside or incorporate a false ceiling to accommodate services, this is both labour intensive and costly as well as impacting on the floor to ceiling height.


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## clonboy

i just installed the precast floor last week, putting in the 75 mm screed tomorrow, i like it and expect it to be a good job,, bit more work later on with services,, but it was installed in 2 hours,,, u can only do this once is what i say


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## sas

It's been posted here a few times in the past that the biggest mistake people made when building was not going for a precast first floor.

It's a great feature. It's also not as expensive as I would have thought. My plans have approx 2000sq ft of precast and the quote i got was €5600 inc VAT installed. 

I was in a house recently that was under construction. Couldn't help but jump up and down on the precast first floor (I'm a big child..) and it was as if I was jumping on the road outside. Not the slightest bit of movement or noise. I don't think you'll regret it.


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## leex

For fire reasons alone, I'd go with precast.


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## galwegian44

Nina - I did this 8 years ago when we built our house and it is definitely worth it. It's not that much more expensive and for safety reasons alone I would recommend it. Having said that the most obvious benefit is if you have a bunch of kids playing in the bedroom(s) and you don't hear a sound. Another potential benefit is that it gives you the option of designing the upstairs rooms in totally different dimensions to downstairs i.e. you don't have to place internal upstairs walls on downstairs walls. Another benefit that I loved (although it is a minor one) is that you can (and should) build your upstairs internal walls in block and then your bathroom accessories etc can be plugged and screwed in place rather than screwed into plasterboard which inevitably will be pulled off by kids at some point.

All in all it's a no brainer...imo



nina said:


> Hi, I'm hoping for advice as looked through but can't see any at the minute. My husband and I are building and wondering should we put in precast concrete floor upstairs. We think it would be worth it for soundproofing. His dad says that we should just double joist the upstairs and that that would be fine and a lot cheaper. We want to put in wooden floors upstairs. Has anyone experience of either (good or bad) that they could share? It would be much appreciated.


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## nina

Thanks so much for all the advice. Really appreciated. Galwegian, I know what you're saying about putting fittings into plasterboard, as that is the way it is in our current house and total disaster. Great to hear from people who have them. I'm decided..it's a must! Now, I saw on another post that someone got precast floors from a company in Monaghan and they didn't need the screed, just grout between them. Any experience or ideas on this? Cheers.


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## sas

nina said:


> Now, I saw on another post that someone got precast floors from a company in Monaghan and they didn't need the screed, just grout between them. Any experience or ideas on this? Cheers.


Like this?

[broken link removed]


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## wigster

Believe me go with concrete. This was the only thing that I did not go for and am I sorry. I have pulled up the carpets flooring due to noisy joists and I still cant get them right. What a mistake I didnt go with it.


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## Nedtastic

How about going down the more environmentally route and go for the I-Joist.

[broken link removed]

No connection. Just satisfied customer.


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## mikeor

I am in the process of a self build.
Am building a bungalow, but converting upstairs.
Am going underfloor downstairs and upstairs.
Am thinking about putting in concrete slabs at 1st floor level but I want to spray plaster the underside of the slab.
this means that all electric wiring must run on top of the concrete slab.
Am wondering has anyone else done this construction method.

Two options i think im left with at first floor level:
1) Put in concrete slab. Then first fix wiring. Then pour screed. Then insulation, then underfloor heating, then finished floor screed.
2) Put in concrete slab. Then screed. Then first fix wiring. Then insulation. Then underfloor heating, then finished screed.

The option of going with joists would eliminate the wiring issue as the electric cables would run between the joists. Could pour screed on top of the joists but want to go with concrete slab option.

Any opinions?


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## Nobrain

Hi Nina, if you are considering UFH upstairs you would need poured screed anyway, so perhaps there would be plenty of sound insulation without the concrete slabs? Does anyone have any experience, as I am thinking of doing this?


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## conorMac

We currently live in a 2 storey detached property that has wooden / timber flooring which is very noisy. I would love to remove them and add precast flooring and was wondering what exactly  would be involved.

For instance - could some of the floor be replaced whilst some left as is or is it better to replace all and does it involve damage to the ceiling on the ground floor.

Many thanks
Conor


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## Leo

conorMac said:


> We currently live in a 2 storey detached property that has wooden / timber flooring which is very noisy. I would love to remove them and add precast flooring and was wondering what exactly  would be involved.



Not possible as a retrofit I'd imagine, walls and foundations won't have been specified to carry this considerable weight.


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## noproblem

The precast flooring is put in place by a crane. Doubt if you could add it to an existing house with the roof on. It's ok people looking for advice, but to not understand the weight and installation issues is a bit silly, to say the least. Another thing that people are not mentioning with the precast method is the subject of ceilings below the precast. This can be done by battons, but the suspended method is the proper way to go. On no account plaster over the precast, some people actually do, wouldn't advise that at all. If you can afford it, it's the best way to go, if you can't, it's not the end of the world. The people in the house are what matter.


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## lowCO2design

conorMac said:


> We currently live in a 2 storey detached property that has wooden / timber flooring which is very noisy. I would love to remove them and add precast flooring and was wondering what exactly  would be involved.
> 
> For instance - could some of the floor be replaced whilst some left as is or is it better to replace all and does it involve damage to the ceiling on the ground floor.
> 
> Many thanks
> Conor



http://www.karma-acoustics.co.uk/easy-panel-timber-floor.htm



these were just two product suppliers I got from a quick goggle search

rockwool and gypro etc have acoustic solutions also and may be best as they'll get a rep out to meet you


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