Lime advice

[vicky whitworth]

I've got a lime question. I have been rebuilding the stone work on my rubble stone outside privy and mortaring it in with lime on a 1 part lime to 3 well-graded sand. That's been OK but the mix is pretty sloppy. I have not added any water and tried to keep as much water away from the whole thing except I have been spraying the wall as I go. I now need to start pointing it up (it's only rough so it doesn't need to look fantastic) but I can't point with the sloppy mix. Am I doing anything obviously wrong? Should I change the mix for pointing?
Many thanks, Vicky

 

[MdB]

If its sloppy then its too wet which means that it will shrink more as it dries. I doubt this is a problem for the work you have done so far (not really an expert on this) but I wouldn't use it for the pointing.

My guess as to the problem is sand with too high a water content. I have lots of bags like this at home which I have opened the top of so that they will slowly dry out over time. For the stuff I needed quickly, I even went to the effort of spreading the sand over our concrete drive so that it dried out in the sun. An alternative solution is use some hydrate in the mix (I didn't have any spare) rather than just putty.

The stuff you have already mixed up, just leave in a sealed tub for two to three weeks. The water will pool on the surface which you can then pour off.

 

[worms]

The mixes I have been using for pointing over the last couple of weeks have seemed too dry when I was mixing them, but have produced a much better result than previous attempts. I've given up on the putty in favour of dry hydrate and bagged sharp sand, mixed dry and then just a hint of water added using the sprayer. I have tended to make up a bucket-full at a time (which is enough for an hour's therapeutic pointing in the evening) and use it the next day. It doesn't hold together like a proper mortar when it is on the board (consistency more like a rather course version of soft brown sugar) but it has packed well between the stones and is easy to work smooth. I had my doubts about the hydrate, since I bought it last summer and had used a little last year but it has hardened well so far and my fingers are crossed...! I am also assuming that the deeper I get into the bag the less chance there is that it has carbonated.

Of course, some wise soul on here will doubtless tell me it is all about to fail!

 

[biffvernon]

The stuff you have already mixed up, just leave in a sealed tub for two to three weeks. The water will pool on the surface which you can then pour off.

That's it, except that it may be ok just to leave it overnight - there will be clear water on top that can be tipped off.

 

[Mark]

I'd agree with everything thats been said.

How wet is your sand?

Where did you get the lime putty and how sloppy is that? If you made up your own and its very sloppy then its just that you used far more water than you needed for the amount of lime. You can leave it until it settles properly - which might take time - pouring off the excess water as you need to or add more dry hydrate.

My first batches of putty were very sloppy and took quite some time to settle, as I've made more I've refined my technique. I now get as much lime as possible into the water and it is usable next day without any problem.

My plastering technique is still rubbish though.

 

[vicky whitworth]

Thanks for the advice so far. I got the putty from Limebase in Somerset and I've kept it for nine months so it should be good. Once mixed with the sand (got from local builder's centre in plastic bags and seems dryish) the mortar is like rough museli but so sloppy I sort of pour it off the trowel and onto the wall. I'm going to have a go at drying the sand as suggested for the pointing. When I take the putty out of the tub I try to drain off as much water as possible before mixing it with the sand.

All that said I'm really pleased with the progress on the walls so far as the privy has gone from imminent danger of collapse to looking quite respectable (in a rough, outdoor lavvy sort of way). Have gotten hold of some old floorboards today and intend to cobble together a sort of thunderbox inside which I plan to secret a bucket for the purposes of 'bucket and chucket' as I've heard that human urine is a deterent for deer (which have eaten all my roses).

 

[Nemesis]

It's good for the compost heap.

 

[Penners]

Which is why I conscientiously make sure that I can produce a lot of it.

 

[Nemesis]

Yes, recycle the beer is a sound plan.

 

[Mark]

seems strange that mature putty and dry sand is giving such sloppy mortar.
I'd try either mixing the mortar and leaving it toi dry a little (overnight?) or adding some ordinary building sand to it to stiffen it up.

Hopefully one of the exprts will have an opinion.