The mortar in new in block work has dried over 5 days it is sandy and falls out when touched. Is the right?

Question

Also what can I/ he do to fix this

Answer 1

geaff w is wrong. it should be 5 parts sand, 1 part cement and 1 part lime is the correct mix. the builder is a cowboy.make him take it all down and start again using the right mix. also make suru he does the render properly.

Email me at:- [e-mail]

Answer 2

Sorry I'm no builder but I am pretty sure you have used too much sand and not enough cement. Why did you not look on the net for instructions on how to do this?

Answer 3

it should not fall out. After 5 days it should be hard. What sort of temp are in you are in ?if to hot not so good.

I would be concerned normally it will not fall out a bit of the surface may as a little bit of grains of sand that is all.

Answer 4

sounds like too much sand to your mix or not enough mixing

Answer 5

no its not right,,,,you/or builder have used too much sand and not enough cement,,,,3 parts sand and 1 of cement is about right for mortar, your ad/details concerns me a bit i thought we were talking "garden wall" you are saying a building,,,if thats the case then your builder is a "cowboy" and you should bring in your local trading standards officer,,,check if this" builder "is a member of a recognised federation or guild...ie master builders federation,or any other they provide a guarantee of their members work,,,,if this is a building rendering wont cure it,,it wants pulling down and re building,,,,

we had this some years ago with "alumina cement"cut the cement to make bigger profits,,lay 2 inch on motorways instead of 6 inch makes profits,falls down quickly and the builders get paid again to repair their shoddy work they should have done right in the first place,

is the firm called "Bodgeit and Scarper!"

Answer 6

It's the result of a weak mortar mix. Too much sand and not enough cement isCausing it not to bond. Don't be fobbed off by him saying he is going to render it. Tell him you want it rebiult with a stronger mix. Don't pay a penny to him until you are satisfied with the work, and don't pay him any extra money for correcting his own mistakes.

Answer 7

Have you got any professional advice? Are building control invoved? If you don't have a proper specification you will have difficulty controlling this, I would condemn it if it was supposed to be cement mortar as it sounds as though it is probably too rich (or too lean). But basic British Standards (assume you are in UK, or is only the US that have cowboys?) cover this. He has a duty to build properly and in conformity with the regulations. If it is lime mortar, it might not be such a problem - especially if it will be protected by render. You should have a contract in place that allows you to retain some money against defects appearing, but if you haven't got that in place by now, it is a bit late.

Answer 8

I don't know who the "he" that you are referring to is,but he's definitely NOT a professional tradesman. Take heed of all the good advice in the answers above & I will add to it. DON'T pay him any more money,DON'T get him to render it & get some advice from your  local CAB &/or a professional builder

Answer 9

it is wrong

the correct mix is whatever the manufacturers recommend for their blocks/bricks ie there is not one mix of 5:1 or 4:1 for everything, plasticiser can be used instead of hydrated lime

the answers all say the mix is weak or uncured which is correct

rendering covers the wall to improve weather resistance and give a decorative finish. it is NOT there to hold the wall up

do not let him do anything else until you get a surveyor in or call up building control to see if they will come and have a look and advise. it will cost but it will be worth it when you have to kick this clueless halfwit off the job and you do not pay him. he may give you a hard time and threaten court so you need a professional assessment of the rubbish he has done so far

dont pay him anything

dont let him do anything else

Answer 10

If using a thermalite or similar block yes the mortar would have to be a weaker mix 7part building sand to 1 part cement this ensures that the strenght of the cement will not eventually crack the blockwork. However you should not be able to rake the joints out after 5 days. If a concrete block has been used then ordinary 5parts sand to one part cement should suffice. If thermalite blockwork used ask the builder to apply a slurry coat of Ronafix to the wall prior to rendering otherwise the render will eventually blow from the blockwork dont let him use Unibond this is for internal use only.

Answer 11

RJ and Geoff are both right to an extent.

The more likely cause however is that the mixture dried out too quickly and the mortar did not have enough time to 'cure'.

Firstly, if the blocks were not soaked before laying, they can sometimes draw out the water from the mortar like a sponge.

Secondly, if the blocks were laid in a high temperature directly in the sun, the same thing can happen, they should be covered with wet sacking so the mortar can 'cure' naturally.

Answer 12

You may get some sand brushing off the very outside, but otherwise, no, it should NOT fall out.  I'm afraid you've got a bodger, not a builder - especially when taken with your previous question about him running out of cement.

Answer 13

He need to remove the blocks and start over. If you let him proceed, you will end up with a collapsed wall.