Ask a tradesman

Bricklaying

Does adding washing up liquid to mortar weaken it?

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!

15 Answers from MyBuilder Bricklayers

Best Answer

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.

2011-02-19T22:45:02+00:00

Answered 19th Feb 2011

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

2011-02-20T13:10:02+00:00

Answered 20th Feb 2011

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

2011-02-19T22:45:02+00:00

Answered 19th Feb 2011

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

2011-03-11T11:20:02+00:00

Answered 11th Mar 2011

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

2011-02-20T09:15:02+00:00

Answered 20th Feb 2011

you should use plasticiser as opposed to
Washing up liquid

2011-02-20T22:40:01+00:00

Answered 20th Feb 2011

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!

2011-02-20T13:10:02+00:00

Answered 20th Feb 2011

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 !

2011-02-22T21:10:01+00:00

Answered 22nd Feb 2011

Why would you use washing up liquid when it is more expensive than plasterciser!

2011-02-20T09:15:02+00:00

Answered 20th Feb 2011

Always use feb mix never washing up liquid but only above ground level

2011-03-25T20:45:02+00:00

Answered 25th Mar 2011

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.

2011-02-20T19:35:02+00:00

Answered 20th Feb 2011

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..

2011-02-19T22:45:02+00:00

Answered 19th Feb 2011

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

2011-02-20T22:40:01+00:00

Answered 20th Feb 2011

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

2011-04-30T08:50:04+01:00

Answered 30th Apr 2011

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.

2011-02-20T13:10:02+00:00

Answered 20th Feb 2011

Post your job to find high quality tradesmen and get free quotes

Can’t find an answer? Ask a new question

Question Categories