Concrete footing or not?

[biffvernon]

Sue wrote on the old forum

Hi

I've been quite on the forum for ages, I seem to have turned into the local handywoman and decorator and have been busy. I come back and find two types of forum. Not really sure where to post, but most of you old hands seem to still be on this version, so I've registered for the new but will post my question here in the hope of finding the advice I need.

I have to get around to rebuilding part of my garden wall that collapsed during the winter now the weather is better. It's a thick stone wall, (2 walls with rubble infill in between really). Not having built a wall from scratch, someone local has kindly offered to start me off and show me how to lay the stones etc. I will be using a lime mortar, but think I should be able to get away with hydrated builders lime and sand for this one as it's not the house walls. Any comments/thoughts on that?

Now the offending area has been cleared down to ground level I'm in a quandary. The man who is advising me wants me to dig down 12" and lay a concrete footing a few inches wider than the wall to build off. But I can't for the life of me understand why. The rest of the wall doesn't have concrete footings and has been there for ages.

Can anyone who knows how to build a rubble filled stone wall in a traditional manner advise me on how to start it off. It has to tie into the existing wall at both ends, so if I make the base of the repair rigid I'm sure it will crack at the joins where the old wall can flex. The finished height of the wall varies, but is probably about 3.5' high.

I've saved all the old rubble and soil that came out of the wall to reuse. Should I add any lime to the soil before stuffing the cavity or will plain soil and rubble do?

Tried and tested methods much appreciated.

Thanks in advance.

Sue

Hi Sue,
You absolutely do not need concrete footings for the wall you describe. If you are building a mortared, rather than dry, stone wall, then don't use any Ordinary Portland Cement. Lime, the dry bagged hydrated lime from any builders merchant is just fine. I would use a mix of about six parts sand, one part clay rich subsoil, one part dry lime. Don't buy the subsoil - just use what you dig up where the wall is going. Pass it through a coarse garden sieve, mix it all dry and then add as little water as you can to get a workable mortar. Cheap, low embodied energy, and if in a few hundred years time someone doesn't want the wall it can be taken apart, the stones reused and the mortar will go back into mother earth from whence it came.
Remember that cement is only to be used in motorway bridges, multi-storey car-parks and airport runways. And we don't need any more of them.

 

[Sue Wilkinson]

Thanks Biff. I didn't think I'd need a concrete footing. Would you recommend digging down a bit and laying the first couple of rows of stone below ground level?

How handy is this, the farm over the road is having a lot of work done at the moment and there is a huge pile of subsoil spoil mountained up about 20' away from where I need to work. I don't think I'd have enough soil for the mix from the area itself, but me and my wheelbarrow won't have far to go for the rest!

Sue

PS Not sure if I've replied to this right, so it might end up as a seperate post. If it does, sorry.

 

[middi]

HI.

Good advise from Biff.
When you consider that the majority of Garden stone walls were simply layed dry and usually tapered towards the apex on no footing at all, I am baffled that it has been suggested you should have a cement base footing.

You are quite right about your doubts, it will stiffen it and in time it will not settle like a stone wall should

If you want to use mortar, that is fine, as long as cement is not used becuse this will also have a stiffening effect.

A tapered dry stone wall, topped with loose coping stone " soldiers", a nice wisteria scrammbling on and off along its length with a flowering cherry in the background..........

-------What a lovely sight-------

( just dreaming )

 

[Schoolmarm]

But dry stone walls DO have footings. Flat interlocking stones are laid about 2 to 3 inches wider than than the bottom of the wall. They are placed lengthways in and staggered. This ties the two sides of the wall together and helps prevent the wall from collapsing as it settles in.

 

[geoff]

Go to the dry stone walling association site - http://www.dswa.org.uk - and look under 'books, leaflets and tools' on their main page. They have a number of free leaflets (look in the left hand panel) in pdf format for download as well as booklets for sale. The wall specification leaflets and retaining wall specification leaflets are extremely useful (using lime mortar doesn't change what it is you are looking for) and they are free to download. I have downloaded many of their leaflets - they are invaluable for any stone walling as they tell you exactly what you should have.

 

[Schoolmarm]

Even though I am a member of DSWA I think you may find the BTCV books are better.


http://handbooks.btcv.org.uk/handbooks/content/chapter/218

 

[Sue Wilkinson]

Thank you Geoff, Schoolmarm and Middi

(How do I reply to a comment individually? I can only seem to reply to the whole thread?)

Anyway, your advice is good and much appreciated. Don't worry Middi, there isn't going to be any cement used in anything I build. I'm a seasoned lime woman these days and actually can't plaster or mix up the modern alternatives because I've never tried.

Schoolmarm, thanks for the words about the footing stones. I would like to do this bit of wall dry, but I can't really as it is just about 18' of a very long wall that has been repaired and built in different ways over time. Most of it is mortared. Although some remains more or less dry, this section is bordered by mortared bits.

I do have the flowering cherry on the other side of the wall, its been lovely the last couple of weeks. I would like to put soldiers on the top, but the whole wall is caped with mortar and so I can't just do this little section with them, it would look daft and I can't spend the time changing the whole wall this year. The jobs list is too long for that.

I'm now going to look at the book and download section of both of your recommendations.

Thanks everyone. The best thing about this forum is that we all have our own little experiences and skills so you can always find the answer to any quandary you might have.

Sue

 

[Penners]

(How do I reply to a comment individually? I can only seem to reply to the whole thread?)

Welcome to the new forum, Sue. Actually, you can't reply to an individual post the way you could in the old forum. The usual technique (I've learned) is to do what I've done above, and quote a few words from the post you're replying to, in order to link in.

But actually, I think that's really the only disadvantage to the new forum. And there are several advantages that outweigh it - you can go back and edit your post if you want to, you can see the whole thread while you're typing your message (just scroll down), you can send private messages to other members, and so on.

Anyway, it's nice to have you back.

Penners (he who was David Penrose in a previous incarnation!)

 

[Gervase]

This is getting confusing - I saw this thread and thought "haven't I posteed to this?", only to realise that it was in 'another place'. Anyway, Sue, see my reply there to your costings question...
And as soon as we have just the one forum, the better (and I do prefer this one)

 

[Chris Somerset]

I have built and repaired some lime/rubble walls recently, in Carboniferous Mendip limestone. The old walls have footings consisting of a couple of layers of really large stones, up to a cubic foot each, below ground level - which seems very sensible to give a firm base for what goes above.