More durable lime renders and mortars

[Anonymous]

I have a croft with a house and steading built from granite boulders with lime mortars and renders. I repair these with lime but have one problem - and that is durability in the areas where livestock are kept.

The byres are lime rendered internally to a height of five feet, but the pigs in particular are fond of digging the render out, and often the lime mortar between the boulders as well. I have to spend at least a day a month making repairs and would rather spend the time doing other things!

Is it possible to get a harder mix without using cement, or should I just bite the bullet and use some cement in the render. (Bear in mind that above the render, the boulders and mortar are exposed but as that's above animal height it's not a problem as far as durability is concerned.)

I can't use board (like Sterling or marine seven-ply) to protect the render as pigs and sheep tend to nibble on them, and I don't want them ingesting formaldehyde and the like.

Also, has anyone else had a problem with rats eating the lime mortar out? While we have a constant war on vermin, I'm continually find tunnels and overhands gnawed through the mortar by rats.

Any advice appreciated.

 

[Anonymous]

First of all -adding cement to the mix probably won't make it more durable, if you read the findings of the Smeaton project it makes it less so.

If you need a harder mix then the addition of a pozzolan or use of a feebly hydraulic lime will give you that - although you will lose some of the properties of a non-hydraulic it's possibly better than having constant damage. I'd give one of the lime specialists such as Mike Wye or Old House store a ring and ask for recommendations.

As to the rats - thankfully ours haven't started on the house yet - so I can't comment but can sympathise.

 

[Anonymous]

That should have read tunnels and overhangs!

 

[Anonymous]

rats have the ability to chew through concrete.... but not for long if broken glass is used as part of the aggregate - much used by local farmers. is it worth having 'salt lick' installed at low level for the pigs to put them off chewing the mortar?

 

[Anonymous]

A pozzolan does seem to make the mortar much harder, as does using a strongly hydraulic lime - some below-ground areas that I repointed last year with NHL 3.5 are now almost as hard as cement.
One of the problems, though, is that any lime mortar takes time to achieve is maximum hardness, and pigs aren't going to hold back while it carbonates. With that in mind, try using a pozzolan, as that will certainly speed up the set and also make the resulting mortar harder.
I use Metastar, but brick dust, pulverised fly ash and other silicates all seem to work.

 

[Anonymous]

Of course you could look on this as an opportunity to give the beasts a vertical salt lick!



Home-made Molasses Urea Blocks for livestock

 

[Anonymous]

The pigs prefer the lime to the salt. Hmm, maybe they'd like some tequila as well? <IMG SRC="http://www.periodproperty.co.uk/discussing/smileys/smile.gif" BORDER=0 ALT="">

I had thought of using broken/ground glass in the mortar, but it would only be in areas where I don't keep livestock.

Rats are a real problem - they can't get into the feed bins but they gnaw through just about everything else. I shoot them, gas them, trap them, poison them, smoke them, and all it seems to do is make them come back bigger and stronger than before!

 

[Anonymous]

Thanks for that.

The pigs don't go straight in after repairs. They mainly live outside in arks, but come in for farrowing, really bad weather and for final fattening. I have a couple pens in the byre and put them in the one that's been repaired the longest.

However, even lime mortar that's been in place for two years doesn't hold out against them. That's why I need something stronger. (Oh, and the pigs also like to lick the limewash off the walls!)

 

[Anonymous]

Thanks - I'd emailed both Mike Wye and Old House Store (I've bought from the latter before) before posting here, but not heard back yet.

 

[Anonymous]

What about putting some chilli powder into the mix?

G.

 

[Anonymous]

I reckon we've found the only good use for cement - otherwise its early bacon.

 

[Anonymous]

Using cement may slow the process, but animals will still chew it down. While my posting above was tongue-in-cheek, I have used cement as the base for animal feed blocks and sheep can easily gnaw down a hard concrete block once they get a taste for it. I've not tried these blocks on pigs but I would imagine that pigs would be able to wear down concrete quicker than sheep. Boredom may be a factor and provision of suitable "toys" may also help.

 

[Anonymous]

'Dry-lining' with corrugated iron?

 

[Anonymous]

Lining is something I'd consider - galvanised sheets against the wall in question, removable to allow for cleaning when the pigs are turned out. Or maybe some hurdles fixed to angle-iron uprights set into the floor to keep the pigs back from the wall.
Also the boredom factor may be worth considering. I know pigs like to play and fiddle with things - I've seen an old wheelbarrow tyre used to good effect!

 

[Anonymous]

I dont know the answer. I might try wire fencing on the wall before rendering, or corru, or putting something hideous tasting like bitrex in the mix.

Or just attaching wire netting on 2" spacers off the wall.

Granite is hard stuff, wouldnt surprise me if it was ok with cement, but I dont know.

NT