Old garden walls

[overlander matt]

This year's outside project is to rebuild a section of garden wall. It's not really a job I've been looking forward to but I can't put it off forever. I first posted about the walls back in 2021...


I'm interested in a few opinions on how best to proceed. The professionals (structural engineer and a couple of experienced brickies) haven't been much help in deciding whether rebuilding or repair is best. The lean and wobble in the wall have pushed me in the rebuild direction.

I've not come across many similar projects here. Malcolm rebuilt a wall a few years ago but not seen anything similar. The originals are just built on spread footings. I plan to rebuild on the existing footings which look to be OK - a similar approach was taken by the previous owner some years ago on the right hand side of the arch... Are there many risks to this approach ie not pouring a new foundation? I am conscious of the trees growing close to the wall.

It's a total of around 4600 bricks plus arch, pillars and capping. I have sourced around 600 replacement bricks - hard to tell how many will be needed until the wall is dismantled and how many can be turned and reused. I'm banking on saving a lot.

One of the main learning points will be how long this takes. How many bricks I can lay each day - I'm not aiming too high. I'm hoping 120 will be achievable.

Looking at a 3:1 sharp sand:NHL3. 5 lime mix. Our local sand is a bit grey so I have started using one part of white sand for a lighter finish.

Any thoughts on the project much appreciated. The demolition of the wall starts after Easter!

 

[malcolm]

I rebuilt mine because it was wobbly and had a 6 inch lean over a public footpath. Also all the bricks were really badly spalled. It was a slow job and took up most of 2021 whenever I wasn't working. I averaged just below 100 bricks a day. Without all the fiddly bits and cutting bricks for the piers 120 would probably have been achievable.

I used NHL 3.5 but regret it a bit. It shouldn't need re-pointing in 100 years so might save the wall from cement, but something softer might have been better just because it would allow the bricks to be re-used again in the future. NHL 3.5 is a pain to remove from bricks.

Those trees are too close to the wall. Trunks get wider very quickly in house years and they'll just push the wall over again whatever you do with foundations. I replaced my foundations. They were stepped out at the bottom and sitting on 6 inch deep lime. Problem was they were in the wrong place as a big tree had pushed the whole wall sideways by a good 6 inches.

 

[stuart45]

I'd say if you've got the time to rebuild it. You'll probably find that your speed increases with practice.

 

[overlander matt]

Thanks Malcolm.

The trees are a bit of a worry. I can discuss these with the landowner in due course - the ones in the photo have at least a 50cm gap to the wall at present. The photo does close the gap. However, out of shot there is an old walnut tree on the lean growing through the wall adjacent to the wall that I am looking to rebuild. My fear with this is that it falls in a storm at some stage. Hopefully, my new wall will survive it.

Your wall looks good, Malcolm. There's something to be said for your approach with a new foundation and straightening it up. I'll just have to see how straight mine looks at ground level as it comes down. It's another matter how long the dismantling and cleaning of the bricks takes. I'm expecting a good week, maybe two to take it down.

Interesting comments on the lime. I have thought about NHL2 but have quite a lot of 3.5 here already.

 

[overlander matt]

I'd say if you've got the time to rebuild it. You'll probably find that your speed increases with practice.

I suspect you are right. I've never built a large wall before so it will be interesting to see how it goes. There are 180 bricks in a coarse which looks out of reach in a day! Laying bricks with lime seems to take me longer than with cement for some reason.

 

[stuart45]

I suspect you are right. I've never built a large wall before so it will be interesting to see how it goes. There are 180 bricks in a coarse which looks out of reach in a day! Laying bricks with lime seems to take me longer than with cement for some reason.

Getting the mix right makes a massive difference to the amount of brickwork you can do in a day. Using the best sand, minimum amount of water, correct amount of plasticizer and mixing for at least 7 minutes to get enough air into the mix makes it much easier. (This is for cement mortar).

 

[aockenden]

Interesting comments on the lime. I have thought about NHL2 but have quite a lot of 3.5 here already.

You can sort of “synthesize” an NHL 2 by splitting your lime component 50/50 between your NHL 3.5 and some non-hydraulic hydrated lime (also readily available at builder’s merchants). I do it very frequently.

 

[overlander matt]

That's an interesting one. I hadn't considered that. What's your preferred mix for a standard mixer out of interest?

 

[aockenden]

That's an interesting one. I hadn't considered that. What's your preferred mix for a standard mixer out of interest?

Sry what do you mean by a standard mixer?

 

[overlander matt]

It's a normal Belle minimix cement mixer.

 

[a twig]

As opposed to the Baron style forced action mixers which you are supposed to use for fat lime or hot lime based plasters or mortars.

From my experiences NHL based mixes have no issues in a standard drum mixer like yours.

I’ve not tried to do anything involving lime putty or hot lime in a drum mixer so no idea if it can be made to work or not.

 

[overlander matt]

I've never used lime putty or hot lime and won't be starting with this wall project. I've got too many bags of NHL3. 5 to use up...

 

[a twig]

I've never used lime putty or hot lime and won't be starting with this wall project. I've got too many bags of NHL3. 5 to use up...

Definitely wasn’t saying you should!

Was just trying to say that your NHL based mixes are fine in a standard drum mixer as you aren’t doing anything with putty or hot lime (for which a forced action mixer is usually recommended)

 

[stuart45]

With a belle mixer I normally stick one bucket of lime and 3 of aggregate. I've found that to be a reasonable sized mix without overloading the mixer.
I add water with the jet setting on the hose. I find it easier to keep the mix off the back and blades.
At Tech they used roller pans mixers. They actually give a better mix for cement mortar as well as lime. They've quite common for masonry contractors in the USA, but here not so much apart from one's doing resin driveways.

 

[aockenden]

At Tech they used roller pans mixers. They actually give a better mix for cement mortar as well as lime. They've quite common for masonry contractors in the USA, but here not so much apart from one's doing resin driveways.

I think I called every equipment rental shop across Wales looking for a roller pan mixer once, as I was sick of mixing thick sticky insulating plasters by hand. NOBODY had one. Fortunately I found a way to make it easy using a paddle mixer otherwise I would've broken my back and wrists...

 

[overlander matt]

Thanks for the advice. I'm looking forward to getting started after Easter. It's been one of those projects that has had to wait for a long time.

 

[DaveG]

I can give no advice but just wanted to say I look forward to seeing how you get on

 

[overlander matt]

I can give no advice but just wanted to say I look forward to seeing how you get on

I will post a few updates along the way!

 

[Kearn]

I think I called every equipment rental shop across Wales looking for a roller pan mixer once, as I was sick of mixing thick sticky insulating plasters by hand. NOBODY had one. Fortunately I found a way to make it easy using a paddle mixer otherwise I would've broken my back and wrists...

Very very hard to source as a rental. When I did my most recent floor, I got two big Barons from Eden Hotlime.

However, I wouldn’t bother again, I didn’t find they were capable of doing much more volume than my Belle and cost a load to rent. Kept tripping the thermal cut out if I put in anything beyond about 50% of their alleged capacity. Totally defeated the purpose.

 

[Kearn]

With a belle mixer I normally stick one bucket of lime and 3 of aggregate. I've found that to be a reasonable sized mix without overloading the mixer.
I add water with the jet setting on the hose. I find it easier to keep the mix off the back and blades.
At Tech they used roller pans mixers. They actually give a better mix for cement mortar as well as lime. They've quite common for masonry contractors in the USA, but here not so much apart from one's doing resin driveways.

I found a sweet spot with my Belle of 1/2 bag of NHL in a 1:3 ratio which worked well. Ironically I could t get the Barons to do much more than this, even though they claimed a 150kg working capacity.