Lime Plaster and Grouting

It seems a very long time ago that I last used any lime mortar.  It was certainly before the winter set in, but I suppose it was perhaps even September last year.  Well, today I was at it with a vengeance, as I tried my hand at lime plastering for the first time.  It's all very well looking at someone else doing it, and talking about it, but there's nothing like actually doing it yourself, on your own.  There's no-one to blame if it goes wrong, and there's not even anyone to ask for help.  The trouble with plastering generally, but especially lime plastering, is that it's so messy.  If ever I have complained about plasterers being messy, I apologise, as I have found out for myself that whatever you do with plaster, some gets on the (wrong) walls, the floor, all the tools, the ladder especially and of course oneself.

The task was to plaster the old wall which forms part of the rebuilt extension.  It's the wall which forms part of the kitchen and the old brick extension was built outside, so what once was an exterior wall became an internal wall (see photo left).  Apart from this wall, the entire extension is in modern materials but with lime in the pointing to give that softer look.  When we demolished the old extension, I removed all the old plaster (lime and modern pink) on this wall and of course found some lovely Cotswold stone underneath; well, it's coursed rubble, not squared but it's still lovely.  I did contemplate keeping the stone visible but there were several reasons not to.  Firstly, there used to be a hatchway in the wall which I removed and bricked up about a year ago: I had no thought of having an unplastered wall so the bricks seemed a good idea at the time, hence the plastered square in the centre of the wall in the above photo.  I think we plastered it as I thought we'd keep the old plaster (never thought it would come off so easily!).  I don't think I ever mentioned this hatch on this blog, so here's another picture, from the kitchen side (right), before we did the kitchen last June.  The wall is almost 18 inches thick, so it used 70-something bricks going right through to the extension side. 

Secondly, we fitted T-pieces to the water and heating pipes (which you can see in the pictures) to take them through the wall in preparation for the extension.  So these all come out on the extension side, at about a metre up as you can see in the photos.  I've forgotten why they weren't at floor level, which would have been a better idea!  Possibly the second fix plumbing was done after the kitchen fit?  I love hindsight.


Anyway, I managed to do the haired scratch coat on about half of the wall today before getting tired - it is tough on your right arm.  This was two mixes, which I think was not bad considering the spread and his mate used to do five in a day, but I was on my own and my grandson came to see us.  (No further excuse needed!)

I've also been grouting the black limestone floor, which is tedious and, if you're not careful, very hard on your knees; last time (in June) I got housemaid's knee!  So, I've been doing that job in small goes and have now done about 80% of the extension floor, so I'm almost there.  Left, you can see some gaps unfilled, but the rest of the floor is done in the same yellow mortar as can be seen near the camera. I should point out (just in case you've not realized) that the floor and the wall are in the same room, so cleaning up all waste mortar soon after it is dropped is essential to avoid staining on the limestone.  Next time I'll mention my technique for cleaning lime mortar off black limestone (exciting stuff - I must have become a nerd).

Last of the Black Limestone Flags

Well, I hoped to finish the black limestone flags on Wednesday a week ago; I'm pleased to say that I actually achieved this on the due date, to my surprise!  They are not perfect, but then they were never going to be, considering that I'd not done this job before.  Believe me, just because you've laid a few wall and floor tiles of the ceramic variety, don't think that qualifies you to lay a 40mm+ mortar bed and large (i.e. heavy) limestone flags of up to 30mm thickness; it is VERY hard work when you are mixing, levelling, cutting and laying all by yourself.  Apart from the second day, I did two mixes every day and found that this was a decent amount of work which left me tired but not (quite) exhausted.  On the second day I did three mixes and realized my mistake when I sat down in the evening and didn't move for four hours!

Levelling the bed for the individual stone thickness, so that the stone was at the correct height in relation to others, was one problem I had anticipated; I had not realized how difficult it would be to get the heavy stones perfectly square in relation to each other, and with the right gap.  Either they were level but too high, or were sloped, or angled, or the gaps were not right.... or all of these!  You also have to be careful with the order of laying as you obviously don't want to lean on ones just laid.  Since I was doing two mixes and then calling it a day, this wasn't too much of a problem, apart from where I was cutting an edge.  In an ideal world you would lay the stones in the middle and work out to the wall, but then you have to cut and lay the ones at the edge with the wall, so what do you stand on to do that?   My solution was to work with my back to the door (see above), so that the last one was in the doorway, which meant that I laid cut stones against the wall and worked away from the wall.  However, this was my undoing as I dropped the last one in, lovely and level, one cm below the door, and found that it was too small! Instead of 10mm, I had a 25mm gap either side of it, which could have been largely avoided had I measured and cut the edge ones more accurately to suit.  Hopefully, the grouting will hide this sort of blemish, and no-one else apart from Chris will notice where the floor is not level.

I mentioned last time about choosing to use an irregular floor pattern, but forgot to mention how I did the actual irregular design.  I only had three widths of flagstone, 45cm, 60cm and 75cm, all 60 cm long.  I found some unhelpful advice of the internet which suggested that five different sizes was the minimum for an irregular floor.  However, I didn't want to cut them except where they abut the wall as the edges are attractively dressed and I quickly proved that dressing is another skill I don't have (quite apart from the effort in cutting up to 40mm of limestone!).  So I just sat down with a pencil, eraser and squared paper and tried it until it looked right.  Being multiples of 15cm, it was just possible to achieve a layout which looks random, but it was actually hard work, even for an engineer.  The trick with the layout was to not work from the edges; I started designing at the doorway to the kitchen, and moved towards the centre, then worked back towards the edges, as those edges would be cut if needed.  There are two basic rules for an irregular floor. Firstly, never have four stones meeting at one corner; you always need to have a T junction, not a crossroads!  Secondly, don't have long joints covering several stones; for the sizes I have, I decided that three stones was the longest joint I wanted but had to go to four a couple of times. 

Having finished the flags, I moved on to do the floor in the loo and utility (i.e. carrying on out of the door in the photo to the external back door).  The floor in here will be ceramic tiles (450mm square and about 8mm thick.)  These are much easier as they will be stuck onto the bed once it is set, thus giving myself two goes at getting it all level - once with the bed and once with the adhesive.  You've got to make life easier for yourself where you can!  I've done the bed and am now waiting for it to set, so I've gone back to grout the limestone flags.

NB In the photos above, I'm quite pleased with the ledged and braced door you can see.  This is re-used from the old extension, and is fitted in almost the same place with the original latch.  I did have to buy some new T-hinges but even these are identical to the ones I threw away.  I might have to paint it somewhen...

More Black Limestone Flags

We got the first fix plumbing done a week ago, so the time had come to get on with the floor in the new extension.  I bought the black limestone flags some time ago; these are the same as we fitted in the kitchen last May, which looks great (see this link).  Chris and Shane did wonders with the kitchen floor so of course, I wanted them both back for this one.  However, I knew Shane had broken his leg, so Chris was going to do this with me doing all the mixing and cutting.  If that sounds like hard work, yes it is, and I wasn't really looking forward to the job.  Then earlier this week Chris came round and said that but he's been rather busy with a spate of roof work after the recent high winds, so it would not possible for some while.  Time to bite the bullet: let's do it all by myself!  So, I have been really busy this week and can vouch for just how tiring this sort of work can be.

Of course, it is not so clean now

I'll give some detail of the complexity of the task: firstly, you need to decide the pattern for the floor.  Ours would have to be the interesting completely irregular floor to match the adjacent kitchen, so that decision was easy.  Then, there is the question of the mortar mix; I decided to use up the hydrated lime left over from the brickwork on the extension, and a quick internet search gave me a 1:3:10 ratio of cement: hydrated lime: sharp sand (see this link).  For a bedding mortar you must use sharp sand (NOT building sand), so I ordered a tonne bag from the local merchant, which arrived on Tuesday; this had to be barrowed round the back before dark as we had previously had a couple of hundred kilos nicked one night from the front garden!  Now, I have my own cement mixer (right) so I just had to hire a grinder and I was ready to start.  So, I started and immediately found that I wasn't ready as I couldn't find the (previously purchased) disc for the grinder! Sigh...

So next morning I eventually found the cutting disc and now the fun started: make the mix and try to get the right consistency - too wet and you weaken the final mix, too dry and it becomes really hard work.  Then you lay the load to the right thickness (how?) and completely level (really?) so that the stone (of uneven thickness) is nice and level at the right height when laid - perfectly placed in relation to the other flags and correct in three dimensions.  I was matching the level of the kitchen floor (where I started) and wanted to get to door on the other side the room at the right height with a nice level floor in between.

What I found was that I could only do three mixes (or perhaps just two!) before I really became very tired.  This was enough to do about six flags and took me about 4 hours.  Although this sounds really slow, I worked out that actually the two young fit lads would only do about 50% more flags than me in the same number of manhours, so perhaps I was doing OK (at my age).  Of course, the two of them would each do twice as many manhours as me in a day so yes, I am very slow.  I am fairly happy with the result so far (left), although the worst flag is one of the first ones laid - it is ever so easy to increase the depth without realising, and a very small amount on the spirit level is actually quite significant over these lengths.  In one sense, these are actually more forgiving than perfect square ceramic tiles, as they are meant to have character!


So here I am after four sessions without 60% of the floor done - completion next Wednesday perhaps?

Warm, Snug and Cosy

It's been quite a mild winter here so far, with only one really bitter spell, but this last week we have had some persistent 70mph winds - but it's good to be able to say that this house is warm, snug and cosy. The theory of how to eliminate dampness has been amply demonstrated already in our first winter in the house, and we are experiencing the results.

The logic is quite simple really: ingress of water equals dampness, and dampness equals chilly and clammy cold which freezes your fingertips, shivers your spine and generally makes you tired and miserable. By tackling every cause of dampness, from the chimneys on top of the roof down to the ground outside which was higher than the floor levels, we have eliminated the cause of this misery. Now, the expensively heated air in the house isn't being consumed by the latent heat of vaporization (*** see below) of the water in the floors and walls but instead it hangs about and warms us. The radiators are on at a pretty constant setting of about 19 deg C, and if it's a bit chilly indoors we either light a fire or put a jumper on (or both!).

To be honest this drying out has happened sooner than I expected. I knew that I had to sort all the causes of water ingress in whatever form, but I anticipated that the house structure with damp 18 inch thick walls would have taken more than one summer to dry properly. However, they say that 2011 was one of the warmest on record because we had a warm spring and and a warm autumn - the summer wasn't bad but there was no risk of sunstroke here. The result was that the outside air temperature was pretty good for a very long period - just what is required to dry something thoroughly.

Before Christmas I put in some effort to sort out wood to burn, from the copious supply of old rafters, battens and floorboards etc. This effort was largely wasted as we only lit fires on about three days over Christmas! Talking of Christmas, I have mentioned already my two really useful presents: a log splitter and a moisture content meter. The former is still awaiting its first use, as anything I split now can't be used until next winter at the earliest, but the latter has already shown that some bits of wood I thought were dry enough were in fact far too damp - burning damp wood gives poor fires and can damage the stove and the flue. By the same token, the various chemicals used in modern paint and wood preservatives can also damage your fire and, more importantly, yourself. All the wood I mention above is really old and was never treated with anything!

Back to heating and dampness, we made a major step forward with the extension this week: apart from starting the decoration, we have had the first fix plumbing done. Since the house boiler is already working, and the system included supply pipes for the extension, the new radiators have been installed and commissioned. So the extension has heat (what a difference!!) and the remnants of damp plastering are now drying as well (then I can finish the decoration). The floor is next...


*** Water doesn't just turn into water vapour as it warms up (one calorie being the amount of heat required to warm one cc of water by one degree Celsius) - it needs significant extra heat to cause it to become a gas. This is called the latent heat of vaporization. Put it another way, if you warm up water, some of the calories will be used to vaporize it and so will not increase the temperature of anything! So a wet wall requires a lot of heat to dry it, but once dry it will warm up with less heat.