Part 3 -redoing jobs already done and talking about lime mortar

Look before you leap – or duck before you end up in a heap- low door ways

When initially tackling the problem of replacing existing lintels I got stuck in the mind that I am just renewing what is there; that is speak for not thinking things out and leading myself into places I would prefer not to be really; such as mismatching door heights in the entrance.

Well it started with putting the supporting wall in where the chimney used to be, RSJs were put in to carry the floor above, a block wall with steel was the quickest and cheapest and most practical – so yes cement was used where needed. This lead on to having a lower doorway into the parlour room which is picture one; these lintels I had put in at the same time as the window lintels as I was becoming very quick(?) at it and was replacing everything in its original position – mistake. So when the RSJ was put in it gave higher head clearance not to knock your head against every time you walked into the room (sounds a good idea) and coupled with my find at the Traditional Lime Co. store  in Tullow  Co. Carlow of antique matching original pine doors so I just had to take the lintels out.

Practical building tips

However when you look at a wall that has a mix of brick and stone and how everything knits or had knitted together prior to my removing the chimney wall I had my reservations about the stability of the wall under the new lintel. So great care was taken in not disturbing the wall too much, a very important note for anyone working on old stone buildings such as this – DO NOT USE A PNEUMATIC DRILL. Vibration will or could unsettle the surrounding wall and cause it to collapse; the lime mortar is like dust and undisturbed will last hundreds of years but once disturbed it can be catastrophic.

Lime Mortar

Again I use 3.5 NHL in a mix of graded sand  2.5 : 1 lime mortar. I use a small cement mixer, put in a small bit of water and add the 2 shovels of lime to get a slurry mix going and then gradually add the 5 shovels of gravel as they call it in these parts, bit by bit. It is important that not too much water is added as too much leads to excessive cracking; it is ideally a stiffer mix not a typical cement mortar consistency.  Also the mix needs a lot of turning and to aid that I throw in a few fist size cobbles to pound it, typically I would mix for 20 minutes plus.

I admit to being slow at what I am doing – I am not paid by the hour – I would be a millionaire if that is the case! but to prevent the mix which is now in the wheelbarrow from drying out I cover it with plastic and keep it out of direct sunlit. Sometimes if I am being too precious with my skills I have to add a tiny bit of water to get it pliable again – called knocking up –  with a heavy hand but generally in our climate that is rare. If you are working outside and there is a strong combination of sun and wind your mix could dry out too quickly and to counter this spray with water and a cover to avoid excessive shrinkage.

Of course when filling into walls or such I use a good bit of water to dampen the surrounding material, nothing too strong just a pump handsprayer this prevents your mortar from drying out too quickly.

Lime mortar was used sparingly, it was expensive (still is) and was not layered or shoveled on the way cement is now in building a stone wall, so always have a bucket of smaller flatter stones for filling those gaps that occur between stones – the stability of a stone wall is based on stones not on the mortar. So a lump hammer and chisel will eventually produce that searched for stone you could spend an age looking for and cuts down on the amount of mortar you use.

Do not use in wet conditions or if have to cover immediately.

For pointing and dashing drying out too quickly is a problem so cover with hessian or tarp; it has been recommended to me 15 to 25 days considering the conditions but I only have done repointing and roughcast on the exterior walls in late spring and summer – longest I had it up was 7 days as we get very windy weather where we are and it was soon ripped off.

For new exterior it was also recommended to keep dashing layers thin and good drying out times between. My first layer has been on 10 years now — reckon that should be long enough.

Cold weather – setting time is long  through carbonation – (see Pat McAfees best selling book –  Irish Stone Walls for reference – obrien.ie ) and you do not want frost on it – in fact once temperatures drop I never used it outside – a constant temperature is ideal once well into spring  for me – unless working inside with mortar I wait to do work.

Where I was taking out lintels and putting in smaller thinner concrete ones sometimes I had huge gaps around and behind them so once you establish your desired level for your lintel fill in, around and behind them.  Dont leave unsupported stones behind your new beautiful wall front – pack in and use long or big stones to add stability to the wall and so spreading the wall load more evenly.

Tools

Standard assortment of small shovels, trowels, shovels X2 one for gravel and one for bagged mortar.

Cement mixer

Wheelbarrow and buckets for carrying up ladders or for working from on small job to avoid air exposure of main mix and thus causing it to set more quickly

soft brush for clearing out dust and old mortar to leave a clean solid base for new mortar

hard flat specialised brush for tapping in your finished work where pointing on wall surface

low pressure sprayer for water in damping work and surrounding wall – creates greater adhesion to surrounding stone or brick work.

To get mortar in deeper and more compressed use a thin trowel, I use 1/3  and 1/2 inch wide with 6inch long blade, especially if I am putting in mortar to difficult spaces – they are very cheap and save your fingers from all that rubbing and pushing in.

Of course use gloves at all times as the lime is bad for your skin, don’t leave it on you long as it can be painful; wear steel cap boots, eye protection and long sleeves etc etc.

Another good blogsite is cottage restoration – Wexfordthatchcottage.wordpress.com – a finished project – done by professionals – excellent example of full job done in quick time

also see blogsite by old builders company – a goldmine of pictures on a huge range of buildings

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