laying slate floors

[christianb]

Just a quick question...

We're about to put down some large - and I mean "large" - slate flagstones into a refurbishment. The new floor is concrete and onto that I need to put insulation.

Basically, because they have uneven undersides they need to have some form of support (i.e. sand) rather as they would have had (sieved earth) in their original position. Is it therefore possible to simply layer sand on top of insulation boards and then install the flags? I should also say that this is for a kitchen so there might be an issue of water-tightness.

Any thoughts gratefully received.

 

[FamilyWiggs]

Christian,

I had recently done the same - laid 1200x900 35-50mm slate flags over a type of foam insulation. I did this:

Laid insulation boards over floor substrate.
Electric underfloor heating mat taped to insulation
A lime screed (approx 10-15 mm) over the UFH matting.
Slates laid onto the screed.

Seems to have worked fine for me.

You could also of course just lay the flags onto the sand. Not sure about movement though.

 

[christianb]

Many thanks for the reply. Much appreciated.

A lime screed is certainly an option. As for the chances of movement? About nil. Some of these are 6x4ft and 2 inches thick. It took four people to carry one ten yards!

Christian

 

[FamilyWiggs]

Wow - that's big. I thought my 4x2s were heavy at 60kgs! At least I could just about lay them by myself...

Are they all the same thickness? If not, you'll have a nightmare laying them flat - as they'll be too heavy to lift again and chuck more sand/screed under to level them.

I would look at hiring some paving slab lifters.

I learnt the hard way that you must remove *every* trace of screed/grout from the surface and edges of the slate straight away. It discolours very easily otherwise.

Incidentally, where did you get the flags and how much? (if you don't mind me asking)

Robin

 

[christianb]

Hi Robin,

Unforunately they're all slightly different thicknesses. Some are about an inch, some slightly in excess of 2 inches.

As for how much they cost me? A hernia. I was offered them if I could shift them by a member of my wife's family. Both I and my cohorts are still recovering weeks after.

I've no idea how much they're worth, but given that they're over 200 yr old delabole slate, probably somewhere in the region of "you're having a laugh". I managed to salvage enough to cover app. 18 sq.m.

Christian

 

[FamilyWiggs]

Ooh - now I'm jealous. Looked at Delabole slate for our 40sqm project recently - was looking at c£180/sqm !

Have you photographed/noted which order they came up in? You'll want to lay them in the same arrangement in order to keep the worn edges aligned.

When you've laid them, can you post some pics?

 

[christianb]

How much!!??

And I've got the bleddy things sat in my front garden. Mind you, there's no chance of moving them succinctly and I'd only have to look out for people with slipped discs.

Your idea of numbering/photographing for re-laying purposes is a good one. Alas, given that where they came from and where they're going are two entirely different shapes it wouldn't have been entirely practical.

And maybe once I've had a few months rest after putting the blighters down I'll get round to taking a photo!

Christian

 

[FamilyWiggs]

Unless they exactly fit the room you are putting them into, the best part about laying a slate flag floor is that you get to play with a Stihl saw to cut them.

Now that really is a man's tool!

 

[christianb]

Unless they exactly fit the room you are putting them into, the best part about laying a slate flag floor is that you get to play with a Stihl saw to cut them.

Now that really is a man's tool!

Bring it on!(in moderation and paying due respect to the items in question first, of course).