Replacing Concrete Floor & Pipes In Concrete Floor [w/pi

[gjh]

Due to the fact that the existing kitchen floor had sunk by approx 2in in the center [of a not very big room] and had large cracks in it I have ripped up the old concrete floor [which turned out to be not much more than 2-3in thick with big air gaps underneath where the floor had settled away from the floor and there was no footings or insulation beneath the floor].

I plan to replace the floor myself and have excavated down 16in from the desired floor level and plan to replace it as follows:

• 
  2in Screed [to include electric heating]
  2in Polystyrene insulation [with 2in strip around edge up to finished screed level]
  4in Concrete Slab
  DPM [1200g]
  1in Sand blinding
  8in Gravel Infill

Does the above look correct? I'm not too sure as to the best place to put the insulation, under the screed seems to make sense from the electric heating point of view as I wont have to heat the entire concrete slab, however would the screed then be thick enough - am I missing the point of the screed and does this have to go directly on top of the 4in slab with the insulation between the slab and the DPM?

What should the mix be for the concrete slab and the screed?

Was planning on [taken from Collins DIY manual!]:

• 
  Concrete Slab - 1 part cement: 2.5 parts sand: 4 parts aggregate
  Screed - 1 part cement: 3 parts sharp sand

Though will probably have the mix delivered, in which case do you just tell them what you want it for and let them make the mix or do you still have to specify the exact mix?

Finally (!) I also have two pipes to consider, one for the gas and one for the water. Its best to probably picture these:

I will try and carefully hack the remaining concrete from around the water pipe [i dont intend to replace the lead pipe, i'm not that bothered by its presence, I largely drink bottled water and I dont intend to live here the rest of my life!]. I don't really know what to do with these pipes, I don't think it would be a good idea to bury them in concrete but what are you supposed to do with them?

Open to comments, suggestions, help, critisicm, etc!

 

[gjh]

I'm hoping to start this job next week so any advice anyone can give would be gratefully recieved!

 

[masona]

I will try and carefully hack the remaining concrete from around the water pipe [i dont intend to replace the lead pipe, i'm not that bothered by its presence, I largely drink bottled water and I dont intend to live here the rest of my life!]. I don't really know what to do with these pipes, I don't think it would be a good idea to bury them in concrete but what are you supposed to do with them?

You should really be thinking about changing the lead pipe to blue plastic, it's not a questioning of lead pipe poison because the internal pipe would be scaled up to protect you anyway. The problem is most lead pipe are over 70 yrs old tend to start pinhole leaking everywhere. It would be easier to do it now before any flooring is down otherwise damp floor

 

[joe-90]

I'd definitely change the lead pipe. Many house surveys will flag lead pipe as a fault to be sorted - which means money off your selling price.




joe

 

[Softus]

I'd definitely change the lead pipe. Many house surveys will flag lead pipe as a fault to be sorted - which means money off your selling price.

joe

Hey joe - you know so much about houses that you really should become an estate agent when you grow up. With some intense training you could make a real go of it!

 

[joe-90]

I'd definitely change the lead pipe. Many house surveys will flag lead pipe as a fault to be sorted - which means money off your selling price.

joe

Hey joe - you know so much about houses that you really should become an estate agent when you grow up. With some intense training you could make a real go of it!

More pointless abuse from Softus.

I buy renovate and sell property for a living.

joe

 

[Johnboy54]

You're right about the concrete mix - tell them what it's for and they'll deliver it.
As for your flooring make-up, the sand is there to protect the dpc from the gravel, so as long as you mean 1" after all the gravel is covered that should be OK.
On my floor, BC insisted on 5" polystyrene. I don't have underfloor heating, but I guess the principle of heat loss through the ground is the same.
Hope it helps.

 

[gjh]

Thanks for the above, will probably go for getting the lead replaced now as didn't know about estate agents picking up on that sort of thing. Whilst the plumber is around I'll ask him what i'm supposed to do with the water & gas pipes and I'll let the forum know what he says...

5in of insulation, that seems a bit extreme to me? As you might have guessed I haven't been to BC for this job, didn't know I needed too! I guess we'll soon have to get BC approval before wiping our ar$£s in the future! Not sure I want to pay £100+ to get this signed off as who will ever know in the future [bearing in mind the state of the previous floor!]. I think I'll give them a bell for some anonymous advise first to see what they say...

 

[joe-90]

It's not the estate agents but the prospective buyer getting a survey on the property. They'll want to 'negotiate a discount'.


joe