Botched garden wall

Bindone2

Recently had a wall built by a local builder and all the mortar seems to be falling out, this wall was built approx 2 years  ago… the mortar even falls out just with your finger nail, now he is saying must of been a bad batch of cement which I supplied all building materials which was delivered just before the weekend as he was starting the job on the Monday. He agreed to re point the wall which is now also falling out… just reaching out for advice  to see what could be the best cause of action on this, is there a way to get the mortar tested… any help and advice appreciated. Thanks 

stuart45

Mortar can fail for a number of reasons. Too weak a mix, too much water added, old cement, freezing conditions, are some of them. You can have mortar tested, depending on how much you want to spend.

mexican_dave

Don't think there is much point in having the mortar tested, it's failed, you know that. If you are going to use the test report as "a stick to beat" your builder with, I doubt that will get you anywhere. He has already put up his defence: you supplied the cement, so he is saying it's your fault. Doubt you can win this!
This shows a flaw in buying materials. Suspect he used only part of your cement, but used it on another job! Making himself extra profit.
Unclear if he has repointed the wall after you challenged your builder, or if it's still to do?
Back to basics: mortar is a bedding material for the bricks or blocks in your wall.
1) If the mortar crumbles under your finger, then all is not lost. You need to rake-out or cut out all the mortar joints about 20mm deep (I have seen the bulk of this done with an angle grinder with a couple of discs stacked together to match the thickness of the mortar joints [not very H&S] with any remaining mortar removed with hammer and chisel - ouch!); Next dampen the work to be repointed (stops a dry background sucking the water out of your mortar - weakening it - maybe the bricks or blocks were too dry when the builder laid them - didn't dampen them?) and work-in a suitable mortar mix (suggest 1:3 cement/sand). Finish the face of the joint with "pointing" of your choice, I find dragging a 22mm copper pipe along say 10mm joints very effective.
2) If your defective mortar is so weak it falls out like sand in an egg-timer then might have to re-build the wall and foundations. As it's likely the "sand" (there's not much else) will find it's way out over time, and the wall will become unstable.
It might be possible the builder used the cement properly in the foundations, until it virtually ran out, then skimped the cement on the brickwork/blockwork. Sorry lots to think about here.

JohnB47

You are saying that your builder put the wall up and pointing was poor and he repointed it and it was poor again? Blimey, that's very odd. Even if he used the wrong sand/cement mix first, he would surely use the correct mix the second time. Unless his lack of expertise in building a wall is equalled by his lack when repointing. What does the repointing mortar bits feel like. Are they soft/hard/brittle? Are they shallow (repointing done not deep enough)?

As per mexican-dave's post above, even if the original mortar is weathered or poor, repointing can save the day, provided the mortar joint is raked out deeply enough and the repointing mix is correct. Otherwise the new mortar seam simply won't have enough actual brick to get a grip on and will eventually loosen.

FreeBear

mexican_dave said: 1) If the mortar crumbles under your finger, then all is not lost. You need to rake-out or cut out all the mortar joints about 20mm deep (I have seen the bulk of this done with an angle grinder with a couple of discs stacked together to match the thickness of the mortar joints [not very H&S] with any remaining mortar removed with hammer and chisel - ouch!);

A cautionary tail from a house that was attacked with an angle grinder - https://www.periodproperty.co.uk/forum/threads/lime-pointing.17884

If the mortar is soft & crumbling, rake it out with hand tools (a plugging chisel should do the job nicely). In the wrong hands, an angle grinder will make a right mess of the brickwork.

Bindone2

Mortar was falling out from original build of the wall I.e would come out just with rubbing your nail along… just after advice on the subject as the builder has been out and re pointed, this is now falling out 5-10mm thick i would say, As builder has said could be a problem with the cement, which is why I was asking if mortar was possible to be tested as I can’t find a way of knowing who is at fault… what I do know is I must  of thrown at leat 6 bags of cement away thinking I had brought the right amount of cement for the amount of sand needed for the job, so is the mix not strong enough… again I don’t know I’m not a builder, I just know I have paid for a wall to be built and I am feeling I need to rip it down and get another builder to build it. Thanks 

ThisIsWeird

Bindone2 said:

Recently had a wall built by a local builder and all the mortar seems to be falling out, this wall was built approx 2 years  ago… the mortar even falls out just with your finger nail, now he is saying must of been a bad batch of cement which I supplied all building materials which was delivered just before the weekend as he was starting the job on the Monday. He agreed to re point the wall which is now also falling out… just reaching out for advice  to see what could be the best cause of action on this, is there a way to get the mortar tested… any help and advice appreciated. Thanks 

Could we have a pic of this wall, please? Close ups of the mortar lines too.
Is this builder 'reputable', known in the area, recommended to you?
As said by others, mortar might fail due to builder incompetence in a number of ways - the wrong mix (but, blimey, it would have to be seriously out), freezing before it's set, water evaporated before it's set, or the cement was well out of it's 'use by' date. Possibly others too.
In theory the supplied cement could also have been 'faulty', but I have never actually heard of that happening, and if one bag has faulty cement, then many thousands of others must surely have so too! And that would be a lot of crumbling builds! I would therefore suggest that 'faulty' cement is extremely unlikely.
Do any of the above seem likely or plausible to you, when you think back to the wall construction - was it very cold or very hot, for example?
And, after he repointed the wall, this is also 'falling out'?! What do you mean by this? Is it crumbling again, or is the solid pointing falling out a mortar sticks?!

Bindone2

Yes a reputable builder I would say maybe 7 to 10 staff I’m just trying to find a reasonable solution as like you say would be highly unlikely that it’s a faulty batch as there would be others like this… hence why I also say is there a way of testing to say otherwise. It just seems to me that maybe not enough cement in the mix, and then when re pointed that falls out because t it’s got nothing to adhere to… as said looks like repointing was done to a depth of maybe 5-10 mm. Thanks

ThisIsWeird

Is the new falling-out pointing also crumbly, or quite solid?
(And 5-10mm is nowhere near enough :-(. )

stuart45

A rough guide is double the width of the joints for raking out depth, so normally around 20mm for brickwork. Strength of the mix depends on the type of brick and how exposed the wall is. Normally would be between 5.5/1/1 to 4.5/1/1 sand/lime/cement, although could be stronger for engineering bricks.

ThisIsWeird

Bindone2 said:

what I do know is I must have thrown at least 6 bags of cement away thinking I had brought the right amount of cement for the amount of sand needed for the job, so is the mix not strong enough

Did you buy sand and cement? If so, how many bags of the former, and how much was left at the end?