How a builder's creative tip helped me in my farmhouse renovation

As explained in September’s article, this summer’s project was helping my neighbour repair two unruly, but potentially handsome, façades that were constructed a century or two ago out of round river stones (galets) and bricks. 

They had been badly patched up in later years and needed some deconstruction and a new, more sympathetic fix.

The first phase was to dig away any material that was loose or about to crumble with a chisel, hammer, drill and an assortment of brushes. That done, I could now start adding material instead of taking it away. 

Hiding the cracks

First, I filled any deep holes with pieces of broken brick and a rough and ready cement mortar. 

Then I attended to the two vertical cracks. I had to ascertain why these had opened up and make sure the cause had been addressed. 

One, for instance, was due to a badly repaired doorway in which the lintel was not doing its supporting role. The other was caused by damp before the roof above had been refurbished.

Now for the finish. The bottom part of one wall was beyond saving – there was too much concrete plastered onto the stones. 

The best solution for this was a coat of lime mortar plaster to cover up all the defects. I was loath to hide the stones but sometimes you have to put realism before aesthetics or the job will never be done.

For the remainder of the two walls, I wanted to keep all the stones visible and that meant reinforcing and smoothing out the mortar holding them in place and filling in the gaps between them.

The objective was to get a good, uniform mortar finish that allowed the individual stones and bricks to be seen in their best light. 

The obvious method, I thought, was to fill around each individual stone and brick with lime mortar, making it as neat as possible. 

Read more: What repairing our French farmhouse taught me about tiling

Builder's creative tip

I started doing this and would have carried on had I not heard about a technique recommended by a professional builder. 

When he explained it I was initially sceptical but agreed to give it a go, and it is with experience that I tell you about it now.

First, make up a large quantity of lime mortar. It must be as sticky as possible – wet, but neither too dry nor too sloppy. You will have to see what works through trial and error. 

Next, position a builder’s trough of this mortar beneath the part of the wall you are going to be working on, put aside your trowels and filling knives, and pull on thin “surgical” plastic gloves – normal, thick DIY gloves will not give you the sensitivity you will need. 

Now, with great determination and confidence, scoop up a good handful of the mixture and throw it at the wall just where you want it. With luck, it will stick. 

If it does not, press it with your hands to make it stay where it is supposed to until it dries out just enough not to drip or budge. 

Inevitably, the first time you do this large amounts of the mortar will fall away back into the trough to be reused. Gradually, you create a vertical mess worthy of a kindergarten project that partially covers the stones and bricks.

Sculpt the mortar

Leave your handiwork to set for a few hours – overnight works well – and when you come back you will find that the partially dry mortar is soft enough to sculpt. 

Scrape away the excess from the stones and bricks, and tidy up the rest as you please so that you have a reasonably uniform result. 

When you are done, you can leave the mortar to properly harden in peace.

This method was much quicker than my original plan and the result far more satisfying. It still takes time and patience but I will certainly use it again.

The only remaining problem is the very top of the east-facing wall. That is going to need a separate solution, which I will explain next time.