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Bricklaying & Repointing
Have I got Problems With My New Build
Anonymous user 28 February 2024 - 4.07 PM
I have just had the brickwork part of a summer house built a week ago, using 200 engineering bricks and 200 Topcrete standard solid 7N blocks 440 X 215 X 100MM.
I am not pleased with the completed work and would like to ask several question to the community.
1, To lay all the brickwork 450kg of sand and 2 x 25kg cement have been used.
The bricklayer says he has done a mix of 5:1, the above quantities don't seem correct to me.
2, The mortar turns to dust when rubbed with your finger.
3, Pressing on the mortar in some places it crumbles, in other places its solid.
4, The building is at some time going to be rendered, by another person. The builder who has done the brickwork says his work is ok for the rendering job to be done. I am not too sure about this.
5, How long do you have to leave the brickwork/mortar before you can render.
6, I have noticed lots of big gaps between the brickwork where the mortar goes on the up parts (perps). They range from 8mm up to 38mm. Should this be the case.
Any feedback on any of the above questions would be greatly appreciated.
Are you a tradesperson and able to answer this question?
Ratio should be 4/1 (4 part sand to 1 part cement for brick work above dpc (damp course level) anything below dpc should be 3/1. With my experience and knowledge I belive the mix is to weak. Also every joint should be full and no holes what so ever. Do you know if he has used mortar plasticiser? washing up liquid should not be used
As a tradesman your observations seem alarming. Without seeing the job I cannot comment further but think you should employ a surveyor to write a report .
4.1/5.1 mix would be fine. Alway check the cement manufacturers ratios. These will be found on the rear of cement bags. Blue Circle probably the biggest Uk supplier reccomend 5:1 ratio for mortar. Your problem is the mix used in your construction is 9.1.
I would consider contacting a contractor to come and inspect the work for you. They will give you some sound advice if they know what they are doing.
Regarding the render, I would always leave fresh block/brickwork for at least 2 weeks or you will get cracks as everything settles down.
The real issue you have is, with mortar that weak the building is going to move, guaranteed.
Answered14 August 2023
1
Anonymous user
4 and 1 – 4 sand 1 cement for brickwork and you must be consistent some brickies mix 5 and 1 if they are using soft bricks. Brick joints should be filled – perps and beds. If you have open perps, you’re probably using a brick-liar not a brick-layer. Before rendering the mortar must be cured for at least 7 days, weather temperature considerations, to prevent cracks from appearing in your rendered surface as the mortar mix dries.
