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Bricklaying & Repointing

Does adding washing up liquid to mortar weaken it?

Anonymous user 23/02/2024 - 2.30 PM

I'm assuming that proper plasticiser doesn't weaken the mortar (given that it's so common), but what does washing up liquid do? I've been surprised to see how common the washing up liquid trick is. No one seems to worry about it but me!

Are you a tradesperson and able to answer this question?

15 Answers

Anonymous user

Never use washing up liquid in your mortar mix. The only place for that is on the kitchen sink. Use mortar plasticisor.
Answered20 February 2011
24

Ace plastering & building services

Rating: 4.9 out of 5
Maidstone
Basic washing up liquid acts as a plasticiser, but reduces the final set strength of the mortar. Many washing up liquids also contain soluble salts, which cause temporary efflorescence and are hygroscopic.
Answered19 February 2011
23

Adam Bosley Brickwork and Paving

Rating: 5 out of 5
Pontypridd
I use concentrated mortar plasticiser, you add just 10ml to a mix(standard belle mixer) It comes in 500ml or 1 liter bottles and has a measuring cap on top its far more practical than standard plasticiser once you get use to it and according to the manufacturer it strengthens the mix! Using fairy liquid can create bubbles and lead to voids in the mortar. Would a wall acctually collapse purely beacause of fairly liquid? Unlikely, but I would not be seen using washing liquid as its not a proffesional image. Regards Adam
Answered19 February 2011
23

Anonymous user

you are better useing a proper plasticiser when using washing up liquid when set it seems to dry really white probably salts coming out whitch is noticable
Answered11 March 2011
22

kentish builder

Rating: 5 out of 5
Canterbury
hi,the days of useing washing up liquid have long gone now.you can buy good quality plastisiser from any good building supplier.thanks nick
Answered20 February 2011
20

C Glancey

Rating: 5 out of 5
Motherwell
you should use plasticiser as opposed to Washing up liquid
Answered20 February 2011
19

Anonymous user

never use washing up liquid it kills the mortar and give the wall a couple of years and you will be able to dig the mortar joints out with your fingers.anyway plasterciser is not expensive but even if it was its cheaper than a new wall!
Answered20 February 2011
16

Anonymous user

Why would you use washing up liquid when it is more expensive than plasterciser!
Answered20 February 2011
11

Anonymous user

Plasticiser is the new washing up liquid, dont like to say it but used to use it years ago before the proper stuff came out on the market - Trust me washing up liquid has a weakening affect on mortar, do not use it !
Answered22 February 2011
11

Anonymous user

Always use feb mix never washing up liquid but only above ground level
Answered25 March 2011
9

northview property mainenance

Rating: 5 out of 5
Welling
its a big NO NO. ive heard storys of people having to pull there work down because of this. plus the proper plasticiser only costs about £6 and will last along time..
Answered19 February 2011
8

c grimwade brickwork

Rating: 5 out of 5
Colchester
you should never use washing up liquid it will kill the cement, in time your mortar will start to crumble.Always use a plasterciser and you will have no worries.
Answered20 February 2011
8

Anonymous user

hi dont use washing up liguid thats for pots ha ha allways use plasterciser you will have no worries
Answered20 February 2011
5

Anonymous user

its something to do with the amount of bubbles coating the sand and it can not be controlled when using washing up liquid
Answered30 April 2011
5

Anonymous user

I have seen builders use this and seen the end results which were not good.It looks quite funny when you see a builder mixing and he is stood there with the fairy bottle !!! You are always better using a good quality plastisier.
Answered20 February 2011
4