Help required - Big concerns with mortar mix

I'm not sure if anyone can help but I think I may have a big problem with the extension I am building.

The extension is quite large and is a conventional brick and block build. We used 6200 bricks and about 1100 blocks and between 50/60 25Kg bags of mastercrete. It appears the brickies that laid all the brickwork used a lot of platerciser in the motar mix i.e. 78Liters. Back calculating how much placticser should be used it appears they have used enough for 624 bags of cement - approx 10 times the suggested maximum dosage. In addition matercrete also recomend that only half the amount of suggested platisicer be used as matercrete already includes platiciser. So you could say 20 times the amount required was used.

The problem is that now (about 10 months after the brickwork was completed Aug 07) we are getting some very large cracks appearing in both the brick and blockwork, many sections are loose and both the bricks are blocks are falling out in sections.

Has anyone come across this problem before. I would be very interested to hear from anyone that has seen an example of overdosing or could suggest someone who may be able to provide an inspection to confirm/squash my worst fears that it has to come down.

Local BCO has visited and will only state that where it structurally unsafe it will need to be corrected.

Brickies have been back to visit and have suggested we could get away with repointing specific areas (I am not so sure)

There is a lot of money and time involved in this project so any comments/advice would be most welcome.

The mortar is useless if they've put that amount in there. Potential serious issues there, unfortunately. Just dealing with much the same problem on a house with NHBC cover and that's all got to be raked out, tested further in and probably every course wedged to permit remortaring complete. Many ££££s.

There is no positive news for you on this, I'm afraid .

Many thanks Shytalkz.

Hearing from someone who has come across this issue before and to get a example of what they are planning to do is extremely useful. Other peoples experiences really help as there is very little info on the net and it is very difficult to find any engineers with any experience of the problem.

Every word you wrote I have taken on board and it has already helped me, thank you again.

I would welcome any further comments from yourself or from anyone else; everying is useful.

Sorry that I couldn't be more upbeat.

This is the company that the NHBC are using to do my particular job. Might be some info on there of interest to you. I have a meeting with them on site in a couple of weeks, if I can glean any more info, will let you know.

Afraid I can offer any sort of practical help on this topic – but out of interest have you asked the brickies why they used that amount of platerciser?

78 litres is a pretty exact amount – did you supply the materials yourself for the job? Do you have any evidence linking the brickies activities to this amount of platerciser? Could be useful if you decide to go down the legal route with them.

Thanks again Shytalkz. The Gun-Point Technical pages are most useful, there is a lot of good technical mortar info and it is all adding to my knowledge on the subject.

I am determined to remain positive though. I cant walk away from the problems. Besides there a lot worse thinks that can happen in life and when you get weather like is today not everything can be bad.

Hi Kingandy2nd

Yes, I supplied all the materials myself. I still have all the cannisters and was here all the time the brickies were on site so I know it was all used in the build. 3 x 25L drums and just over half a 5l container.

My problem is that in order to prove anything conclusive I will need to have some expensive testing done. And then, if we go to court and just say I won, I still have no guarantee that I will be able to get any money out of them.

Basically my plan is to identify just what the problems are, find out what effects that will have (short and long term) and from that I can then decide what needs to be done to recify things. If I can keep the brickies on-side and involved ideally we can agree on the faults and hopefully they will either correct or help correct the faults. I know they are a good bunch of guys and their reputation is important to them so an informal, low cost approach is the best approach. Also, from experience to start shouting about and thowing my toys out the pram rarely gets anything significant done.

Just remember that whatever the mortar is like where you can see it, ie in the joints, it's going to be like that right the way through the thickness of the leaf. Don't be fobbed off with a mere repointing exercise, it will come back and haunt you at some point in the future.

I can’t believe these brickies are any good or have any sort of reputation if they make such a basic error when knocking up some muck.

If I were you I wouldn’t be asking them to rectify the job – you may just end up with other problems, I would be getting someone else in to sort out their mess.

How do you know that the state of the brickwork is related to the plastisicer?

And how do you know that all the plastisicer was use in the mix and not splilled/poured into a bosh and then the water used for other purposes/ taken off site for other work?

You have to get some samples tested before you can move forward.

Also what were to contract terms for these bricklayers? Were they contracting to you directly or a builder, who provided supervision and instruction for the work?

kingandy2nd said:

I can’t believe these brickies are any good or have any sort of reputation if they make such a basic error when knocking up some muck.

If I were you I wouldn’t be asking them to rectify the job – you may just end up with other problems, I would be getting someone else in to sort out their mess.

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Why is it a basic error - how do you know that the sand did not need livening up for it to become useable?

And the contractor has to be given the opeortunity to correct the work or decline

And how do you know it is their mess when we don't have all the facts?

If the quants of plasticiser are as suggested, the mix would beef hooked - totally.

And, yes, if it's their fault, then they should be given the opportunity to rectify any defects (or decline the opportunity to do so), as Woodster says.

Woody I very much respect your knowledge and you've helped me out a few times in the past.

However, the poster said he watched these brickies use all the stuff and no matter how much livening up the mortar needed, using about 10 times too much smacks to me of someone who doesn't know what they're doing.

The poster has given the gang an opportunity to rectify their work and they've suggested a bit of re pointing.

It is only my opinion, but if I was in that situation I wouldn't be wasting my time with these guys anymore. I would cut my losses and get someone else in to rectify.[/i]

I agree Sire, but it is really important to determine if the mortar is substandard and what this actually means to the structure as a whole, before doing anything else.

I don't think its mentioned if the brickes work is otherwise bad, so it may be a case of an over enthusiastic laboureer or something. And presumably, their first response to some cracked mortar would be repointing.

But if the mortar is sub standard, then when presented with the facts, then the brickies may be inclined to offer to do more or to agree another solution.

Everyone makes mistakes - however big!

Woody, thanks for your comments.

I don't think the brickies are bad, they worked hard and the quality of the work otherwise is very good. The labourer was also the same and although young had worked with the brickies for a number of years (and still does).

My gut feel is that he was a bit, as you say enthusiastic. I suspect the mix was 'hungry' as the sand was a bit course and with the fact we were using mastercrete, the weather in july being around 20 degrees and possibly the bricks/blocks a bit porus sucking the water out meant he was trying to help them out as best he could.

Just for reference all the mortar is even in colour and I know the labourer was gauging all his mixes so they were consistent. The mix was meant to be 1:5 however I cannot confirm if that is correct or not. I have now confirmed the exact number of bags of cement used to lay the 6200 bricks and 1100 blocks was 45 x 25Kg bags of Blue Circle Original Mastercrete. The Labourer could have knocked over the platiciser but I am pretty sure he didn't as I cleaned the mixer at the end of every day and there would have been signs. No other intermediate barrels were used on site for mixing, it was straight from container to bucket to mixer. The brickies were also on this job for the whole time so it would be unlikey for them to filter any significant amounts off for other jobs (especially as it's cheep).

I agree totally that I need to 'determine if the mortar is substandard and what that means to the structure as a whole' however I am finding it extreemly diffiuclt to determine that. If I can get some testing done it will only give a general indication of the sample being tested (sand/cement mix used, air content etc). It will not be able to tell me what effect that will have on the whole stucture as it does not take in to account the other variables such as mix variances, Brick/Block properties, weather conditions, water content etc. Every stuctural engineer I have contacted seems to back up that assumption; most seem to rule themselves out by saying 'it is not really my field' or 'if you get some tests done on the mortar first' I will come and take a look then write a report. I suspect getting a real definitative decision is going to be near impossible and it's going to be down to me to do that based of as much info as I can get.

It would be interesting to know if anyone can tell me what an overdosed mortar mix would look like and what the effects would be. eg. would there be aheasion problems, would the mortar be soft or hard and brittle. Would the mix be too airiated and thus provide a reduced contact patch or would the increased airiation mean less water in the mix (and combined with the porus bricks and warm weather) would it therefore affect the hydration process. Also could the Autumn rains or large amounts of efflorecents had any contributory effects.

The Brickes are coming back on Monday and will bring along the other senior partner to give his oppinion and make a proposal for what they are willing to do.

I would be interested to hear any suggestions on what I should do.