Grouting Close-Set Pamments

[Flyfisher]

Last year I finally started working on the last room in the house that needs total renovation, so the end really is now in sight or at least coming into view (apart from a lot of decorating, but somehow I manage to ignore that particular aspect of things).

The floor is somewhat odd, being half pamments laid on earth and half suspended floorboards over a cellar. The floorboard section was also higher than the pamments, with two small steps down to the pamments, effectively dividing the room. The pamment floor was below the outside ground level, which unsurprisingly had caused penetrating damp (goodbye skirting boards!). I had already reduced the external ground level as far as I reasonably could, given the shallow foundations, but it was still level with the pamment floor, so not ideal.

A plan was hatched to lift all the pamments, lay an insulated limecrete floor with UFH (based on the Mike Wye foamed glass model - https://www.mikewye.co.uk/limecrete-floors/) and replace all the original pamments. This would raise the new floor above outside ground level and level with the floorboard area. UFH was proposed as I didn't really want to clutter the walls with radiators. LBC duly granted, this work started late last year and the floor was left to thoroughly harden.

I'm getting to my question :wink:

The pamments were originally laid tightly adjacent to each other with no defined grout lines. I don't really know if anything specific was originally used between the pamments or whether there was just a build-up of general muck over the decades (centuries?), but whatever it was was not loose, all the tiles sat firmly in place and nothing was sucked up when vacuuming the floor.

Naturally, I want to re-lay the pamments as they were and have been laying them as close together as possible, which is perfectly fine although there are naturally a few small gaps between them. And therein (finally!) lies the question - what to do with these small gaps? - I'm considering a few options:

1. Just leave them as they are and let time do its work, clogging them up with the inevitable 'muck' that floors attract.
2. Fill them with kiln-dried fine sand by brushing it over the surface
3. Fill them with a dry mix of kiln-dried sand and NHL lime in the same way
4. Fill them with just dry NHL lime in the same way.

I've not seriously considered attempting to grout them by brushing over with a wet lime mixture because of the risk of staining the porous pamments, which might be possible to remove with brick acid but even so would take ages. Similarly, I've not considered trying to hand-grout using a wet mix because it would be nigh on impossibl. I can't even get a knife edge between most of the pamments so even laborious hand-grouting would result in significant spillage and therefore staining and therefore laborious cleaning.

Option 1 seems a bit of a cop-out. Option 2 would likely be undone the first time the floor is vacuumed. Option 3 seems feasible and the hope is that residual damp in the floor and pamments would cause the NHL lime to harden over the next few weeks, which would eliminate the vacuuming issue. Option 4 is there simply because I'm wondering if there is any need for sand at all.

So two main questions really: 1 - have I missed any other options? and 2 - what does the panel think would be the best option?

 

[LadyArowana]

5. Which is really a version of 1. Vacuum the rest of the house with a Dyson, empty contents on relaid floor, sweep up badly getting only the big bits and let the rest go in the gaps. Repeat at daily intervals. In a little over a week you’ll have authentic period detritus filling the spaces.

I love my vacuum, but I’m convinced it is actually a machine which makes dust grit fluff and hair. It always finds stuff even when not a soul has been around.

 

[Me!]

3. Fill them with a dry mix of kiln-dried sand and NHL lime in the same way

Several years ago I laid a sandstone patio and then grouted between the slabs using a dry mix of NHL3.5 and sand. The mix got nicely damp from the ground beneath, but it never set at all.
I also used that exact same bag of lime on the same day to make a conventional wet mortar with the same batch of sand, and that all hardened perfectly.
I still don't understand why the dry mix didn't work, but if you go down that route I strongly suggest you try a test patch first to see if it will work for you.

 

[Flyfisher]

5. Which is really a version of 1. Vacuum the rest of the house with a Dyson, empty contents on relaid floor, sweep up badly getting only the big bits and let the rest go in the gaps. Repeat at daily intervals. In a little over a week you’ll have authentic period detritus filling the spaces.

I love my vacuum, but I’m convinced it is actually a machine which makes dust grit fluff and hair. It always finds stuff even when not a soul has been around.

What is this 'Dyson' of which you speak Milady? Our Henry is wondering if it cold be a long lost relative :wink:
Interesting idea to accelerate the natural process, although wasn't it Quentin Crisp who said something about dust not getting any worse after a few years, so perhaps an additional boost would be required.

3. Fill them with a dry mix of kiln-dried sand and NHL lime in the same way

Several years ago I laid a sandstone patio and then grouted between the slabs using a dry mix of NHL3.5 and sand. The mix got nicely damp from the ground beneath, but it never set at all.
I also used that exact same bag of lime on the same day to make a conventional wet mortar with the same batch of sand, and that all hardened perfectly.
I still don't understand why the dry mix didn't work, but if you go down that route I strongly suggest you try a test patch first to see if it will work for you.

Hmm. Perhaps mere damp is not sufficient to facilitate the carbonation process, which is a bit of a surprise. But being a patio was it not exposed to rain and did it not set even then, or was it under cover?

Sounds like a test patch is definitely required. I'm wondering if lightly misting the floor with a water sprayer would help the NHL to set.

 

[Me!]

The patio is not under cover and the joints all appeared to stay nicely damp for several weeks.

Here is the thread that I posted at the time - https://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=14097

 

[LadyArowana]

What is this 'Dyson' of which you speak Milady? Our Henry is wondering if it cold be a long lost relative :wink:
Interesting idea to accelerate the natural process, although wasn't it Quentin Crisp who said something about dust not getting any worse after a few years, so perhaps an additional boost would be required.

My Ms Dyson is like the tall skinny trophy wife of the slightly portly Henry. Rarely used but with powerful suction and showy appearance as required.

 

[88v8]

I've not seriously considered attempting to grout them by brushing over with a wet lime mixture because of the risk of staining the porous pamments, which might be possible to remove with brick acid but even so would take ages. Similarly, I've not considered trying to hand-grout using a wet mix because it would be nigh on impossibl. I can't even get a knife edge between most of the pamments so even laborious hand-grouting would result in significant spillage and therefore staining and therefore laborious cleaning.

A hybrid...

Where they are tight I would do nothing.

Where there is a gap I would wet-mix with NHL/sand, using silver sand if necessary to get into the gap.

I would mask the edge of the pamment with good masking tape, wipe it off with sacking and remove the tape before fully dry.

If there is not too much to do it might not be overly laborious.

I wet-grouted some quarry floors, it does take a long time and there is a high risk of staining, as you say.

Ivor

 

[Flyfisher]

Thanks for that link Me! I don't recall reading it at the time, though I'm claiming that seven years as my excuse. A little bit depressing though as it's looking like a laborious wet mix of some sort is going to be required.

I think Ivor's suggested 'hybrid' approach is going to be the only practical way forward, though I think I'll try a small test area with a dry mix first, but more out of desperation than hope after all the above comments.

I'm also finding that the floor is not turning out quite as close set as it originally looked because the pamments are not precisely the same size and so cannot always be laid edge to edge as it would distort the geometric pattern. I've encountered that sort of problem before when laying a clay paver terrace and discovered that clay pavers are not as dimensionally identical as concrete pavers, so simply butting them up against each other (as recommended for concrete pavers) soon results in a straight line becoming more of a gentle curve, which then plays havoc with the next row of pavers.

It might also be that I've not done a 'forensic' re-lay (ie the same tiles in exactly the same place and orientation) so all the size variations have been mixed up. These things are never quite as easy as they might initially seem - but that's just the fun of the challenge isn't it? Hmm.

 

[Craig89]

This grouting question is something I am also interesting in finding out as I have quarry tiles and geometric encaustic tiles to lay in the future.

When I lifted my quarry tiles (laid as close together as possible, governed by the slight variation in sizes as mentioned above) and also some of my original hallway tiles that I have lifted and relaid, they definitely had some form of grout between them, it was quite hard and strong, and had a distinctive smell when broken up/chiseled off. I'm sure i have read in an old text about encaustic tiles that a cement slurry was used, how this was done and cleaned up who knows but something is definitely used to fill the small gaps.

 

[a twig]

I have vague memories of using grout application bags with some success to grout flagstones without too much mess, was fairly large gaps though

 

[Flyfisher]

This grouting question is something I am also interesting in finding out as I have quarry tiles and geometric encaustic tiles to lay in the future.

When I lifted my quarry tiles (laid as close together as possible, governed by the slight variation in sizes as mentioned above) and also some of my original hallway tiles that I have lifted and relaid, they definitely had some form of grout between them, it was quite hard and strong, and had a distinctive smell when broken up/chiseled off. I'm sure i have read in an old text about encaustic tiles that a cement slurry was used, how this was done and cleaned up who knows but something is definitely used to fill the small gaps.

I've aways thought of quarry tiles as being almost glazed and certainly not very porous, although perhaps that's just because the ones I've come across have always been shiny and polished. Whatever the reason I've always assumed they'd be less prone to staining than pamments, which have always seems a bit more 'porous' to me. I've never dealt with encaustic tiles though. I'm sure a slurry approach would work as far as the grouting itself is concerned but my worry would be cleaning up the tiles afterwards.

Having said that, I used new pamments (http://www.pamments.co.uk/ on our kitchen floor extension with a definite grout line and an ordinary NHL2/sand wet mix and the little staining I did have was mostly removed with water and a rag as grouting progressed and the odd bit of residue when dry was easily removed with brick acid (actually 'spirits of salts' - basically the same hydrochloric acid but stronger, available in all good hardware stores for unblocking drains and the like).

Similarly, when limewashing an internal wall, the inevitable drops and splashes on the pamments was also easily removed in the same way.

I think I was just hoping for a hitherto undiscovered easier method of grouting rather than entirely by hand and cleaning up as I go but it seems that's really the only practical method. Seems like the state-of-the-art has not moved on since Me!'s earlier thread in 2013. Oh well.

 

[plasticpigeon]

I laid quarries edge to edge in my kitchen. Given the age (c1900) of my house I'm pretty sure the original quarries were grouted with pure cement slurry. However as I had laid a limecrete floor I used a grout from Ty Mawr (If I remember correctly) that was lime with incredibly fine aggregate like marble dust or something. I found I couldn't brush the grout down the gaps dry or pack it in with a dry mix using a trowel, so I had to make a slurry and try and wash it down which worked alright. I'm not sure it went down to the bed, but it was enough to fill in all the gaps and make sure none of them rocked about. They are good 7 or 8 years later or whatever. On the quarries I just cleaned using a sponge and water and lastly used a weak brick acis to get up the slight bloom, but can't comment on pamments. When I got the reclaimed quarries quite a lot of them had cement grout around the edge for about 5 to 10mm from the top surface adding weight to the idea that many were grouted with cement slurry in edwardian times. THe geometric tiles definitely used cement slurry, and I have used this method on a fireplace hearth and a vestibule floor with great success.

 

[Craig89]

When I got the reclaimed quarries quite a lot of them had cement grout around the edge for about 5 to 10mm from the top surface adding weight to the idea that many were grouted with cement slurry in edwardian times. THe geometric tiles definitely used cement slurry, and I have used this method on a fireplace hearth and a vestibule floor with great success.

The first bit of tiling I will be doing will be quarry tiled hearths. What is the cement slurry process? Simply mix cement with water and pour it in the gaps? Then clean up as much with water and a bit of brick acid if required?

 

[plasticpigeon]

Yes that is what I did.