Thorfun

Every day is a learning day..... and this is what I learnt today

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Today I learnt to lay a slab. it's my first one and not a very important slab as it's just to house the GRP electricity kiosk from CCF Fibreglass and a couple of wheelie bins. it was about 0.2m3 and I mixed approximately 1 part cement to 6 parts sand/ballast pre-mix with some water by hand in a wheelbarrow and then tamped it down to get a rough but level-ish finish.

 

There are 3 x 150mm ducts in the slab for the electricity supply in, out to the house and out to the STP which is nearby so these got in the way of getting a nice tampered finish but, all things considered, I'm very happy with what I've achieved today and think I did an alright job for something that I really didn't care how good it looks. 

 

IMG_0382.thumb.jpeg.6f2c25606cee948e1ae297b33713076e.jpeg

 

I'll have another one to do to house the ASHP further down the line which I'm sure will be better.

 

what did anyone else learn to do today?

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Ha, I learnt that block and beam should have a 225mm void over clay, rather than the <150mm my less than reliable builder intends... 

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1 minute ago, Jilly said:

Ha, I learnt that block and beam should have a 225mm void over clay, rather than the <150mm my less than reliable builder intends... 

oh dear.

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I learnt about ovens from my Father in law, what to look out for in terms of cleaning, the control display sizes and so on.

 

2 hours ago, Jilly said:

Ha, I learnt that block and beam should have a 225mm void over clay, rather than the <150mm my less than reliable builder intends... 

Off topic..

 

Don't panic Jilly.

 

NHBC regs touch on this, have copied below their text in italic from section 5.2 D10 of their regs.

 

A minimum void of not less than 150mm should be provided below the underside of floor slabs and beams.

On shrinkable soil where heave could take place, allowance should be made for the void to accommodate the following movements according to the shrinkage potential of the soil:

  • high potential - 150mm
  • medium potential - 100mm
  • low potential - 50mm.

If you get stuck then I would look to see if the ground has recovered from any trees / hedges cut down in the last two years or more.. this causes ground to swell. Also, have a look at what time of year the solum is installed, at the end of the winter where moisture contents are high and the ground has lifted/ swelled.

 

If conditions are right you can make the point to the BCO that the ground has swelled (heaved) upwards close to it's potential maximum so once you put a dry building on top it will go down and increase the void. A reasoned argument coupled with a pragmatic BCO could resolve.

 

This is a bit of last resort stuff to get you out a hole if you get stuck.. say main underbuilding levels set.

 

 

 

 

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I learn the same thing every morning, my body aches.

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so I didn't learn this today but what I've learnt over the last few weeks that the basement contractors have been on-site is that there isn't a problem that can't be solved with a hammer.

 

rebar in the way? smash it with a hammer

formwork dirty? smash it with a hammer

nut won't tighten/loosen enough? smash it with a hammer

 

I'm surprised tool manufacturers make any money as it would seem that the hammer is the one stop tool that will fix anything and anything else is just superfluous to requirements. 

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57 minutes ago, Thorfun said:

so I didn't learn this today but what I've learnt over the last few weeks that the basement contractors have been on-site is that there isn't a problem that can't be solved with a hammer.

 

When all you have is a hammer, everything...

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1 hour ago, Nickfromwales said:

Worlds Biggest Hammer Artwork Stolen

He’s got a big nutter 

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1 minute ago, Nickfromwales said:

Birth defect, apparently. 

I know the feeling …

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26 minutes ago, ToughButterCup said:

I learned about Clearance Holes

 

and now i have :) i am one of the lucky 10,000

 

Ten Thousand

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very weak mix for concrete 6-1 with ballast!!

looking at the cement bag it says 4-1 with ballast mix 

maybe not a big deal with that size for a grp  box

--but bear in mind its something like a foundation for a wall

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4 hours ago, scottishjohn said:

very weak mix for concrete 6-1 with ballast!!

looking at the cement bag it says 4-1 with ballast mix 

maybe not a big deal with that size for a grp  box

--but bear in mind its something like a foundation for a wall

interesting you say that as you're right that the cement bag says 4-1 with ballast mix but the ballast bag says 6-1. so I just made it up as I went along. like you say, it's just a light weight GRP box.

IMG_0792.jpeg.8ad1ae9dea7415e4d846d1e6ef71c614.jpeg

 

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1 hour ago, Thorfun said:

interesting you say that as you're right that the cement bag says 4-1 with ballast mix but the ballast bag says 6-1. so I just made it up as I went along. like you say, it's just a light weight GRP box.

IMG_0792.jpeg.8ad1ae9dea7415e4d846d1e6ef71c614.jpeg

 

so you went for the cheap choice -

as the cement is the active part in the mix--and the people that would get sued --then I believe the cement bag mix is correct .

 more cement will give you a better finish if you float the next one 

 

Edited by scottishjohn

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On 09/05/2021 at 16:50, Thorfun said:

Today I learnt to lay a slab. it's my first one and not a very important slab as it's just to house the GRP electricity kiosk from CCF Fibreglass and a couple of wheelie bins. it was about 0.2m3 and I mixed approximately 1 part cement to 6 parts sand/ballast pre-mix with some water by hand in a wheelbarrow and then tamped it down to get a rough but level-ish finish.

 

There are 3 x 150mm ducts in the slab for the electricity supply in, out to the house and out to the STP which is nearby so these got in the way of getting a nice tampered finish but, all things considered, I'm very happy with what I've achieved today and think I did an alright job for something that I really didn't care how good it looks. 

 

IMG_0382.thumb.jpeg.6f2c25606cee948e1ae297b33713076e.jpeg

 

I'll have another one to do to house the ASHP further down the line which I'm sure will be better.

 

what did anyone else learn to do today?

 

looks good!

 

A cheap float to make a nice finish, if you have a multitool tape it to a length of 2x2 or 4x2 to use as a handle then screw another piece on the end the width of your pad. The vibration will make the conc come up lovely. Wait a bit till its sets a little and the water comes to top. 

 

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