Advice on new external garden wall

[MrWiddles]

Hi
I'm planning to build a new garden wall at the front of our house. The house is built with Suffolk soft reds and lime so I was considering
to use similar materials for the wall. The wall would be double thickness and about 5 bricks high with capping and probably railings.

Having spoken to a builder, he advised against the use of lime on grounds of strength (I have some mature lime mortar - couple years old which I
used for pointing). His argument is that with the house, the weight of the house is actually keeping the bricks together so it's OK there but with
a small wall it wont have enough weight or natural cohesion to keep it together. I assume this is not the case? are there any special considerations
for building small external walls from lime? (Having said this he has no other objection to lime - I will be providing bricks and lime)

regards
Steve

 

[Ian Bond]

Could always add a pozzolan for a quicker/stronger set, or use hydraulic lime if worried about strength.

They must've managed OK in the days before strong cement mortars, when building low brick walls.

I know someone here who's had a lovely wall re-built recently ....

http://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=8717&st=0&sk=t&sd=a&start=60

I'm fairly certain that Pford75 used fat lime mortar for his brick and flint wall, but it would be worth asking.

I'm sure if you ask him nicely he'll be glad to provide more details.

I've found that a lot of builders are very sceptical indeed about using lime without cement. Personally, I'd always try to avoid using any cement at all in a traditionally built structure, but some may argue that it's OK in certain applications.

 

[Ian Bond]

Oops -should have paid more attention - you said soft brick.

The mortar should always be softer than the bricks or masonry, ditto pointing, which is a sacrificial element. The mortar should help accommodate small amounts of movement. Too hard a bedding mortar could cause cracking in the softer walling materials, which would not be good.

Apologies if you know all this - sounds to me as though you do, but the builder's advice has conflicted with that.

Soft mortar is seen as something bad - weak and not up to the job, to be replaced with good strong cement mortar asap. Not so, as you original thoughts were right.

Hope this help - I'm sure others will be along to add more to this and advise further...

 

[Ian Bond]

Some interesting stuff here - good bloke too, got my first ever batches of lime putty from them a few years ago now.

http://www.chalkhill-lime.co.uk/instructional.html

 

[biffvernon]

Steve, your builder is taking the widdle. I built (re-built) part of my 250 year old garden wall just a couple of weeks ago. It fell over last winter in a gale, having been caused to lean at a jaunty angle for many years by a couple of expanding and now very large trees. I used a mortar of 3 parts sharp sand and 1 part bagged hydrated lime from the nearest builders' merchant, mixed and used immediately. The wall is plenty strong enough and would not come apart without a cold chisel and a heavy hammer.

 

[Ian Bond]

I'm sure others will be along to add more to this and advise further...

Told you they would

 

[MrWiddles]

Hi Biff,all

Thanks for this, so you used hydrated lime as opposed to lime putty based mortar?. (I have a shed full, stored under water in tubs I bought a couple of years back).
I now feel reasonably confident that it should be OK. No one appears to think it is a totally daft idea so I think I should probably go ahead.

regards
Steve

 

[Pford75]

I'm fairly certain that Pford75 used fat lime mortar for his brick and flint wall

Correct....I forget the exact specification of the mortar (Andrew our CO post to this forum and may refresh my memory) but I do recall that there was no pozzolan and that it was perfectly possible for our builders to construct a fairly large wall (which has a soft red brick core similar to what you describe) with no need for cement etc. We even extended the work into the end of September (which is a little late for lime work, but was ok).

If it's important, I can dig out the details of the exact mix our flint men used....if you are not too far away, they may even be interested in the work!

 

[biffvernon]

The best stuff is always what you've got a shed full of.

 

[Lime]

If the worry is Joe Public pushing it over then that can happen with cement too.
If that is the case I suggest some internal support.
Steel reinforcement bars would do as used for concrete.

 

[Moo]

... some internal support.
Steel reinforcement bars would do as used for concrete.

If you go ahead with the metal railings, perhaps you could incorporate the reinforcement bars into the design.

 

[Schoolmarm]

It sets rock hard though. Just because we describe it as soft makes everyone think a push will have it over. No way. You might find old soft crumbly stuff in your house walls but new stuff is really hard. I rebuilt our fireplace in it and thought "oh it is soft I will clean the stone in a few weeks", bad mistake!