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Any views on using Fairy Liquid in a concrete mix

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Greensands24/05/2021 17:49:16
377 forum posts
49 photos

Hi - In a nearby housing development I have noticed the builder is using Fairy Liquid in the concrete mix used for the footings of a new house. Does this have the approval of the building inspectoater and why would you want to do this anyway? I am sure someone will have the answer.

Samsaranda24/05/2021 17:54:35
1485 forum posts
7 photos

The addition of Fairy liquid in mortar used in bricklaying aids the workability of the mortar, haven’t heard of it being added to concrete mixes though, I think that it is frowned upon by authorities because apparently degrades the final strength of the mortar, apparently affects the chemical process. Dave W

Robert Atkinson 224/05/2021 18:24:02
1248 forum posts
20 photos

It used to be common practice. Washing up liquid is cheaper than "proper" plasticiser.
It works by lowering the surface tension of the water. You only need a tiny amount. Don't really see it having much affect on the strength. The main ingredent in plasticiser is sodium lauryl ether sulphate

The main ingreadient in washing liquid is sodium laureth sulphate the same thing

Robert G8RPI.

duncan webster24/05/2021 18:24:37
4127 forum posts
66 photos

There are approved plasticisers for mortar/concrete, and I'll bet they are not a lot more expensive. According to wikepedia correct use actually makes concrete stronger as it reduces the amount of water needed to make the concrete flow, and excess water makes concrete weaker


Former Member24/05/2021 18:26:50
1085 forum posts

[This posting has been removed]

Gordon Smith 124/05/2021 18:27:10
45 forum posts
2 photos

Back in the 1960's we used Daz.

Former Member24/05/2021 18:30:21
1085 forum posts

[This posting has been removed]

JasonB24/05/2021 18:57:11
23076 forum posts
2771 photos
1 articles

Not unknown for the fairy bottle to be filled with proper plasticiser as it's easy to squirt a bit into the mixer if mixing on site.

Although not really needed for domestic footings plasticized concrete is available from most good ready mixed companies and has it's uses.

Best bet is to buy something like Mastercrete which has the additives already in the cement for when mixing mortar or render then you get the right proportions

DC31k24/05/2021 19:03:06
729 forum posts
2 photos
Posted by duncan webster on 24/05/2021 18:24:37:

There are approved plasticisers for mortar/concrete, and I'll bet they are not a lot more expensive.

Could you tell me where to buy Fairy Liquid for less then £3.00 for 5 litres please.

Bill Dawes24/05/2021 19:10:23
539 forum posts

Not a concrete technologist but I would have thought the danger is weakening the concrete with too liberal usage causing foaming.

Bill D.

Rob Wheatley24/05/2021 19:16:00
51 forum posts
28 photos

Bet the mixer is sparkling clean and the builders have very soft hands though. laugh

old mart24/05/2021 20:00:29
3912 forum posts
268 photos

I have used it with cement on a syringe made for injecting it. Without a small ammount of plasticiser, it would be impossible to use. PVA adhesives are also useful in the cement mix, it enhances the adherance to older concrete.

not done it yet24/05/2021 20:20:24
6889 forum posts
20 photos

Enough to form bubbles will very much increase the workability of the mix. Not good for the strength as concrete relies on good compaction for maximum strength development.

Masonry cement, for brick-laying, etc incorporated an air entraining additive to improve the workability and use of mortars where ultimate strength is not required (mortar should be weaker than the bricks/blocks). It is far better to replace brickwork pointing, if building movement causes cracks, than replacing bricks🙂 .

Far better to use the correct additives, approved for the job, than washing-up liquid.

I once had to visit a concrete user who had found low strength concrete (cube testing) results which had been used in concrete pilings. The bulk cement had been delivered by a tanker previously used for washing powder product/ingredient. The concrete pilings actually smelt of ammonia (which presumably retarded the setting of the concrete). I don’t know if later strength tests were accepted or if the pilings had to be replaced. An expensive exercise.

The concrete supplier knew the cause before I arrived - he already had cement samples and cube test results - and I knew of the outside contractor that delivered the dodgy load to the depot - before it was transferred to a company tanker prior to final delivery to the ready-mixed concrete site cement silo. Those pilings might still be propping up something in Linford (now part of Milton Keynes).

Edited By not done it yet on 24/05/2021 20:23:03

bricky25/05/2021 20:44:54
584 forum posts
72 photos

I have run several 4and 2 gangs of bricklayers and fairy is not used in concrete but is better than febmix in mortar and if you lay bricks with our local sand you would be pleased to add a dash of fairy .Used it for all of my fifty years in the building trade and of all of the washing up liquids fairy is the cheapest and best in the long run as you only use a squirt,and after all this time 10years since I retired I havn't seen any deteriation in the buildings I worked on.


john carruthers26/05/2021 09:16:03
616 forum posts
180 photos

As a plasterer's mate I used a few drops in a mixer load as a deflocculant to prevent the mix balling.
Mainly happened with dryish mixes like floor screed.
Never used it with concrete.

Grindstone Cowboy26/05/2021 10:51:07
894 forum posts
64 photos

Veering a bit off topic, but still related to additives... when I was at polytechnic, one of our lecturers was heavily into researching cement additives, and had a number of examples of what was possible. The most impressive was a coil spring, made from sand, cement and additives, about six inches in diameter and height, probably about three turns, which acted in all respects just like a normal steel spring (possibly not as long a life though).

And the flat roof of a power station admin block I worked on had a foamed cement mix laid on top for insulation purposes - specialist mixers were used, don't know what the additive was.

Back on topic, yes, Fairy liquid works (never heard of it in concrete, only mortar), but builder's merchants don't sell it, so just order Feb whilst you're getting all the rest of your stuff delivered wink


Mark Simpson 126/05/2021 11:26:17
111 forum posts
30 photos

There are additives for concrete to make them flow more easily when being pumped or into areas of dense reinforcement... Normally added once the mixer is still on site as it gets very sloppy.... Tarmac call it TOPFLOW, hanson call it easy flow... I had some awkward footings built with limited access and it saved us the cost of a concrete pump, just pulled it along with a rake.... Much preferred structurally to adding lots of water.

Marischal Ellis26/05/2021 11:48:36
77 forum posts
27 photos

Yes I too remember Daz in its powder form back in the sixties. Wasn't liked and would be restricted. I don't think too much would make a difference. Certainly helped to ease working the mortar, but that was alongside very hot bricks straight out the kiln and hosed down, dry sand lying in heaps on the ground and all sorts of other bad practises. Nobody seemed to care. Look at the London flat fire block proceedings 50 +years on......absolutely terrible. If you are responsible, then you are responsible, sharpens the mind no end. O dear perhaps I am too old now but have seen things that would make you seriously cringe. Stay safe everyone.

Mike Poole26/05/2021 11:49:29
3383 forum posts
77 photos

I have heard that washing up liquid can cause excessive corrosion of steel in concrete, this may be total rubbish as I have no authoritative source to quote and irrelevant if no reinforcement is used in the concrete.


Grindstone Cowboy26/05/2021 12:06:24
894 forum posts
64 photos
Posted by Mike Poole on 26/05/2021 11:49:29:

I have heard that washing up liquid can cause excessive corrosion of steel in concrete, this may be total rubbish as I have no authoritative source to quote and irrelevant if no reinforcement is used in the concrete.


Seems feasible as there's a lot of salt in it to thicken it, but then again, cement is a bit on the corrosive side anyway. Some more so than others.


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