Changing the Floor

[Anne]

We are going to be putting in an unfitted kitchen back to where it originally would have been. The room had a concrete floor put in there in the 70's. The concrete isn't level and it's going to be taken up.

I intend to put the old flagstone floor back down which is lying in the garden. I know there is about 4 inches of sand under the existing concrete. I had thought to use a thick bed of lime mortar over the sand and bed the flags into this. However I'm not sure if I shouldn't be using limecrete instead. So I'm looking for some advice on how to do this right.

My other concern is there is a small pantry off this room that still has its original flags with no concrete under them. I haven't lifted them yet to see if they are directly on dirt but I do know that we get slugs coming up through them and I want to make sure that when I put the floor back down I don't have the same problem.

 

[Andrew Bodenham]

Taking out the concrete and relaying the flags is going to be a major job, and one which you need to get right first time.
Have you considered why the flag floor was removed in the first place - possible because it was cold, damp and a source of slugs!
Whilst a stone floor can look great it is also an unforgiving surface, so be sure you want to live with it before you commit yourself.
You need to consider insulation and damp-proofing in the new scheme. Since you propose to excavate the concrete I presume there is not enough headroom to lay the flags on top of the existing concrete?
If it's all coming out then this is an opportunity to put in a good damp-proof membrane (also slug proof) followed by a layer of insulation - you can take your pick depending on your eco-conciousness, but I'd probably take polyurethane slab as a starting point, and investigate the wholemeal alternatives with respect to performance, thickness and price.
Is there a case for underfloor heating?
Finally the slabs will need to be laid on a suitable screed, and there's no reason why you shouldn't use limecrete or a lime mortar for this if you can handle the prolonged setting time.
If you do go ahead the first thing to do is going to be a trial pit to see what lies under the concrete and sand, so that you can determine the depth available for your new floor system.
Note that I haven't actually laid a flag floor in the situation you describe, but have plenty of experience with similar problems. Others with more specific experience may have a more to say on this topic.
Good luck!

 

[Moo]

I very much doubt whether the slugs are originating from below the flags. It's much more likely that they have found their way in from the garden and then moved downwards. My son has found slugs in his kitchen; they came in from his garden but, because his concrete kitchen floor doesn't have any gaps, they stayed on the surface.
If your flags were to be properly pointed (one of the resident lime experts will specify the recipe) there would be nowhere for the slugs to go. All you'd have to do is find out where they got in and block it up.

Flagstones that have been properly laid on earth (with anti-slug pointing, of course) are the most wonderfully labour-saving and hard-wearing surface.

 

[Gervase]

For myself, I'd always try to avoid the damp proof membrane if at all possible to avoid having the damp pushed out to the walls. I can see nowt wrong with taking the concrete out, digging out the floor and then bedding the flags on a bed of sand above a well-compacted layer of hardcore (made from your concrete floor, if you like - there's not much else that old concrete is useful for!).
If you want a more substantial floor, then you can go down the DIY limecrete path - dig down 10 inches, lay a layer of geotex, then four inches of hardcore, well compacted, then another layer of geotex, and then a four-inch concrete slab made from NHL5 hydraulic lime, 8mm-ish limestone gravel and a bit of sharp sand. When that's cured off (allow at least 10 days) you can put on a layer of blinding sand and lime and bed your flags in that, pointed with a non-hydraulic lime mortar.

if you're going to have a thick bed of anything lime you'll need to use hydraulic, as non-hydraulic or fat lime relies on exposure to air to cure, and this won't happen under slabs or in thick layers (or, rather, it will happen, but in your great-grandchildren's dotage!). The pointing, which needs to be the most breathable part of the floor, can be in fat lime because it's exposed to the air and can therefore carbonate.

 

[NT]

Labour saving equals vinyl - just a shame it looks so awful, and traps damp badly.

NT

 

[biffvernon]

has its original flags... I do know that we get slugs coming up through them

I'm still trying to come to terms with these Welsh rock-boring slugs

(PS Marmoleum is nicer than vinyl)

 

[Penners]

I'm still trying to come to terms with these Welsh rock-boring slugs

 

[Moo]

Where on earth did you find that !! ??

 

[worms]

Moo,

Where on earth did you find that !! ??

right click on the image, select properties and you will see the url for the website that Penners got it from. Not sure I would want to follow that link though!

Penners, I see from the picture title that that one is the "normal Heldenverm". I'd hate to see an abnormal one!

 

[middi]

The inside of my stomack must have resembled like that a couple of weeks ago, after an Italian Chinese.

( yes there is such a thing, unable to taste or rcognise any ingrediends).

I should have stuck to mothers spaghetti.

 

[Geoffrey]

Please lsten to Gervase and avoid the DPM. Several walls in my house have been damaged as a result of (now removed) DPM's and concrete.
As long as the ground under your floor is relatively dry you should have no problems laying onto this - it's how it was always done.

 

[Moo]

Worms - are you telling me that it's a picture of a real creature? I thought it was a figment of someone's surreal imagination !

I only have a Mac, so I can't do that clever right-clicking thing.

 

[Penners]

are you telling me that it's a picture of a real creature?

Our garden was full of them. To get rid of them, you just sprinkle salt on their tails.

 

[NT]

has its original flags... I do know that we get slugs coming up through them

I'm still trying to come to terms with these Welsh rock-boring slugs

I thought those slugs were extinct now. They bored do much they just died of boredom.


NT