Anhydrite moisture testing, putting some ideas to you Trusted People

[bugs183]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

There was no airbourne dust with the Raimondi Maixtitina, it runs a low speed, so doesn't belt out dust, it just lies on the floor that was easily swept up.
Sorry Sir amic i didn't answer your question, they hired it from Trimline, it wasn't cheap, i think they're about a grand to buy.

 

[The D]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Well sorry Gary but you must be doing I wrong...

And hear in lies the problem no mater what we do one of you tells us we are doing it wrong even when we are doing it the way we have been told to do it :mad2:

 

[The D]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

There was no airbourne dust with the Raimondi Maixtitina, it runs a low speed, so doesn't belt out dust, it just lies on the floor that was easily swept up.
Sorry Sir amic i didn't answer your question, they hired it from Trimline, it wasn't cheap, i think they're about a grand to buy.

was you sanding to remove laitance or was it just to prep the floor???

 

[Colour Republic]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Responsibility... hey welcome to my world where I’m responsible for everything. Sometimes it's a pain in the arse but for the most part I know things get done right as if it doesn't I’m still the one who will have to deal with it!


You're either not willing to take the responsibility and walk from the job.

Or you do take on the responsibility and do it to your own spec and satisfaction but the key is to charge well for it. For example I can get a basement damp proofed for £1k but if I want a ten year guarantee to go with that then I’m looking at £7k. These tests should be the same, the charge shouldn't relate to how long it took to do, it should relate to how much of your balls you've put on the line (that includes Lynn as she has bigger balls than most of us).

The cost of these tests should be put to whoever is asking you to do it. You want to do the test or you’re not taking responsibility, if the HO or builder won't pay then they are quite within their rights not to and they then take the responsibility. They can go and find someone who will tile it regardless and if it fails it's all down to them to sort out amongst themselves.

For me, no matter what, I carry out works to a spec I'm happy backing and at the cost I need to charge for that or I don't do it. I can't complain that others will cut corners and cut costs, there will always be someone else waiting just round the corner. All I can hope for is educating the customer as to why the works need to be carried out like that and the cost implications but ultimately it's their call.

I get faced with problem substrates everyday, their is always a solution, some cheap, some expensive. It is was it is.

I know multi-trades get a bad name from some but it is exactly this reason why I choose that path and keep everything in house from start to finish. No unexpected surprises.

 

[Colour Republic]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Well sorry Gary but you must be doing I wrong...

Doing it wrong, or doing it with the wrong tools?

I have sanders that can fill a room with dust in a split second, I also have sanders and extraction that are 98% dust free

 

[Gazzer]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

While I am aware of machines that will sand the floor with little dust, they are another expense.....add this to your quote for the job and the tiler is the bad guy again.
These machines are not exactly easy to get or hire around our way. I have been into hire shops and specifically asked for a certain type of machine. I get looked at as if I have just parked my spaceship outside. The other point is that these machines are great for larger areas, not for when they have the kitchen already fitted.

This is another cost that the one man band tiler cant afford.

 

[Ajax123]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

If you want highly controlled and very accurate precision don't use a sander use an enclosed shot blasting machine. These are cheap enough to hire (last time I hired one it was £80 for the day plus I think it was fifty pounds for the shot) these are like a amall vaccuum cleaner with an oil drum sized dust collector attached. I hired it from South Wales for a job in the midlands. It was very much faster than sanding as well and perfectly acceptable for removing laitance or to prep the floor for tiles.

 

[Pebbs]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Heres my take on these screeds, whether we like it or not, there's going to be a lot more around, so we have to get our heads around how to deal with them. Its already hit the commercial side, and it will hit the private side sooner rather than later.

For me its been a bloody nightmare, I do not have a clue when I secure the contract what the substrate is going to be. It can start of as one thing on the drawings then when you get on site, because they are behind with the programme its now this.

No I do not price for the sanding and priming, I was never asked to price for it, and why the hell should my men be expected to do this, when they are already under the cosh to get the contract finished. You wouldn't tile over bonding plaster would you? (don't you even go there with a smart answer). That surface should be prepped and made ready by the screeders, they should be the ones who take the responsibility for handing it over ready to go on.

You want to do it, fine but there's a cost implication, not one of you is running a charity, you get nothing for nothing. Im am fed up with contracts managers telling me aww theres nothing to it...yes there is a lot to it, because you mess up, who are they going to be gunning for? There has to be some training available, because as it stands at the moment, there is for me to much conflicting information, and I don't know what the hell is going on.

Aww I feel better for letting it out.

Lynn

 

[bugs183]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Too right lynn.
I spoke to my local lafarge rep and as usual its the same vagueness. He re kons the screeder should add sanding as an extra cost and told me all the methods of testing, but couldn't tell me whos job it was! There is zero training around or anyone who has been assigned to putting our fears and the rest of the flooring trades at rest, it really is get on with it lads, it'll be ok mmmmmmm.
I'm hoping that my next anhydrite job which i will recommend Creative Solutions GBTA and its primer. I'll do some tests again and let you all know. At the moment this does appear the last ray of light adhesive wise.
If this adhesive proves to have no decent bond with porcelain as the other have shown then i'll be going down the ditra stuck with gypsum adhesive and a cement based adhesive above. Its not my fault it'll cost more, i certainly won't tile porcelain direct to these screeds, regardless of what the reps tell us.
Flooring is 90% of my work and as lynn says where does the buck stop?
i know i can tile to these screeds with ditra but someones gonna have to pay!

 

[The D]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

The adhesive manufacturers that produce cement based adhesives have given credibility to these screeds by suggesting that you can safely install tiles using there primer and there adhesive, this in my humble opinion is not true. If it was true we would not be seeing the problems that we are seeing and the manufacturers of these screeds are now saying if you use cement based adhesive you are at risk of a failure. None of the adhesive manufacturers that I have grilled on the subject are as confident as they make out and some of them openly admit they wish the bloody stuff would juts go away, as do I.

 

[Ajax123]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

I think you may have hit a nail firmly on the head there deano that the adhesive manufacturers are not confident so you get poor or conflicting advice. My own advice has always been consistent and i Am absolutely confident that it is simple to stick tiles to gypsum. THe issue I see is that the adhesive manufacturers (especially the larger ones with a veritable strangle hold on the market) have not responspded by developing or bringing already available adhesives into the uk to suit. Mapei have a gypsum based adhesive in Europe specially for these screeds. Why oh why oh why does the tiling industry not demand that they bring it into this country. Weber have one and what is their fear, that the tiler is too daft to know the difference and will use the spare bag at the end of the job on a cement based screed. Firstly I would give tilers more credit for brains than that and secondly it would actually still stick perfectly well to a primed cement based screed anyway.

As for tilers wanting I get their heads around these screeds this makes my blood boil because the evidence that I have suggests otherwise. Ok a minority may be interested but most are not. I have offered training courses to help educate tilers about these screeds for nearly four years. BAL have offered them in all of their training centres. Most get cancelled due to lack of interest from tilers. my colleagues and i Have offered training in tiling schools, building colleges, tiling outlets, directly with tilers amongst her outlets for education. We have offered to devote our own precious time to getting this much needed mp but apparently not "much wanted" education across the UK. We have offered training to Mapei, weber, nicobond, ultra, and ardex. I would suggest that there are probably in the region of twenty thousand individuals who make a living out of tiling in the UK (I am happy to be corrected on this number of statistics are available) I reckon despite advertising that maybe forty tiling contractors in four years have accepted this training even when it has been free of charge which the vast majority has been. We even ran one for the tilers forums up at perfect home and gardens place and only four tilers turned up. S much for it being much wanted. The most I have seen at once at any of the others is three and as i say most have been cancelled due to lack of interest. of the manufacturers only Ultra and nicobond took us up on the training offers to their staff. Nicobond are the only ones who responded by developing a suitable adhesive although the ultra system seems to work well generally speaking as it is. The big boys are not interested and as far as I see it the tilers are more interested in complaining than about taking up offered of training. The smaller manufacturers like norcross and granfix have seen the market moving and have responded with the introduction of gypsum based adhesives. Kerakoll and benfer both have systems which are compatible.

It is not the screed manufacturers place to say to an adhesive manufacturer that their system does or does not work. that is their job. Sreed manufacturers are experts at screeds. Adhesive manufacturers "should be" experts at adhesives yet most stick with the old fashioned idea that cement is best. Cement is one of the most destructive materials we produce in terms of it industrial impact on the environment. it is also known far and wide that cement is not compatible with gypsum. Well if you always do what you've always done you will always get what you've always had and realistically since these screeds came to market in the UK three decades ago very few adhesive companies have gt on with developing compatible systems. Flipping heck, they even have a gypsum based adhesive manufacturer in Turkey where hese screeds have only been about for a few years. The old objection I used to hear ten years ago was that they were waiting to see what he market does. Anhydrite had already been in the uk for twenty years then. Well guys get with the program the market is using gypsum screeds at an alarming rate of knots. The anhydrite screed market has grown consistently throughout the recession when the traditional screed market has more than halved. We ain't going away. Work with us instead of against us and we might get somewhere for the tiler who is stuck in the middle.

I have never ever avoided taking calls from tilers or anyone else for that matter when they have needed to know how best to tackle these screeds either visiting sites, through pms on here or by telephone and as far as I am aware most of those I have had a personal dealings wwith are now comfortable to work with them.

Pebbs - I offered to meet up with you once I start my new role. I was serious about that offer and Am still perfectly happy to do this and will contact you through here to arrange it as and when you are ready once I restart work.

 

[bugs183]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Good comments there Ajax, there is a huge problem with no one taking this subject seriously, from everyone down from the screed manufacturers, the screeders, builders, tilers and suppliers.
As you say everyone needs to take notice and pull together and certsinly get educated, hence my efforts here to get everyone talking.
Its a shame that adhesive manufacturers and screed suppliers don't get envolved on here too.
So what are the european manufacturers stalling for? Do they want to see everyone have problems and then launch their gear to save us all???
Wouldn't surprise me.
Training wise Ajax i have never heard of any, if i had i'd have been too as many as possible as i understand how big a deal these screeds are.
Maybe you could arrange something for us, i bet more people will attend now.

 

[Gazzer]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

The last training session was in Newcastle, its a bit of a jaunt for some and not so for others.
Central regions are fairer for the majority, obviously some may disagree .
The reason I did not attend was due to the distance but i was one of a few who asked if there would be another session further south....never had a reply !
The way I see it though is until everyone agrees on a method for tiling these screeds....not just Lafarges way or BALs way etc ...but everyone agrees then we continue to have this debate.
Hopefully one day this will all be sorted and we can all look back and say " What was all the fuss about"

 

[Ajax123]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Well if someone wants to arrange a place r places to do some training I wold be happy to get my self there and run a session or sessions. I could get one or two adhesive manufacturers there and deffinitely a few screed manufacturers as well.

What the forums and I guess the tiling industry needs to understand andi mean rell understand is that all this debate in th last ten years has not stalled r even slowed the increase in these screeds coming t market. They have continued and will continue to increase a slow but steady march towards saturation. The benefits are just too huge for the industry as a whole to ignore. Waiting and hoping they go away is just a waste of time

 

[Colour Republic]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Could you not advertise this as niche market? If people really are having problems with these screeds then invariably they go looking for someone with the skills to do it.

I get this with wall coverings all the time. There are tons of wall coverings / wallpapers out there and there are also tons of pastes / adhesives. Careful selection of both is needed to marry the 2 together for a successful installation. For example some pastes can destroy the print on delicate papers as an acidic paste leaches through the base paper and attacks the print sometimes months after installation. A hell of a lot of decorators don't know the differences between one wall covering from the next as most have only hung your bog standard wallpaper from B&Q. For this reason wall covering manufacturers have lists of approved installers, some have formal lists such as Lincrusta where you have to undertake their course to be approved and some have informal lists where they have got to know the installers and are happy to recommend them. They have national databases so when someone purchases their products they also get the advice to use somebody who knows what they are doing. If I get asked to hang a simple wallpaper I am competing against a ton of decorators, if it's a specialist one I get to charge specialist rates as I’ve put the time in to understand what the hell it is I’m working with. It's in the interest of the manufacturers to set up these databases as it means their products aren't constantly condemned as faulty by people that do not understand them.

I see this as the same; it's in the interest of the screeding company’s to provide lists and also the adhesive manufacturers to do the same so they don't get called to failures. The retailers even have lists of local installers so they don't get dragged in to a faulty job.

If these screeds are here to stay then get in quick and become a specialist installer. A lot of decorators are scared of the wall covering I install, that's great news for me as there is less competition. You can fall in to one of 3 categories - Tilers who are scared of these screeds, tilers who don't understand them and **** it up or tilers who have embraced them and become specialists. I know which bracket I’d want to be in if it was my main trade.

A lot of you are already specialists in one area of tiling already; you have a better understanding of say stone, geometric, mosaic or even a certain types of fixing such as sand and cement. I bet you charge more per sqm when you know not every tiler can pull it off as well as you or you have the specialist tools to say polish stone. Embrace and get paid I say!!!!

Alan could a national database be set up from your side of the table? and maybe be distributed to specifiers? It won't happen overnight but all things have to start somewhere.

 

[The D]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

I must come under the scared of it category ! I have gone well out of my way to find out as much as I can about these screeds. I was one of the four tilers that came to PHG to learn how to tile these floors with confidence .I do not put my name to a job unless I am confident that (A) I can cope with the standard of work required and (B) that when I fix the tiles they stay fixed.
I am not confident about anything with these screeds I am not confident about what adhesive to use I am not confident about checking to see if the floor is dry I can’t recommend a method of fixing or materials to use with any confidence what so ever.

 

[jonnyc]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

very well put and i agree with this to an extent.
you obviously work with high end product as well as the norm , and you charge accordingly.
I am the same and i charge a premium for my specialist product knowledge and skill in areas outside of normal domain of works.
the difference in this instance i suspect is that, these anhydrite screeds are are being sold as a fast track and probably cost saving process for ongoing trades.
they are maybe more expensive to install but the impression might be that the contractor is saving thereafter.
But this is not the case , because anyone who is au fait with this product knows that there is loads of aggro to just get to point of fixing and will charge more for thi experienced knowledge.

 

[jonnyc]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

we should not be charging a labour premium to just fix a floor on a different substrate if levels are as for normal jobs.
we just want a substrate that is acceptable.
premium rates are reserved for out of the norm fixing.
the whole point of these screeds are that they should become the norm and we cost these jobs as we would any other. but we cant because there is so much aggr and time involved .

 

[Colour Republic]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

I must come under the scared of it category ! I have gone well out of my way to find out as much as I can about these screeds. I was one of the four tilers that came to PHG to learn how to tile these floors with confidence .I do not put my name to a job unless I am confident that (A) I can cope with the standard of work required and (B) that when I fix the tiles they stay fixed.
I am not confident about anything with these screeds I am not confident about what adhesive to use I am not confident about checking to see if the floor is dry I can’t recommend a method of fixing or materials to use with any confidence what so ever.

Why is that Deano? Is it because you don't believe what you were told on the day and it didn't sit right with you? (as is you're well within your rights to do) or because you followed what you were taught and it still had a failure?

the difference in this instance i suspect is that, these anhydrite screeds are are being sold as a fast track and probably cost saving process for ongoing trades.
they are maybe more expensive to install but the impression might be that the contractor is saving thereafter.
But this is not the case , because anyone who is au fait with this product knows that there is loads of aggro to just get to point of fixing and will charge more for thi experienced knowledge.

That's a different matter and that should be the specifier for the high jump if it has been specified in unsuitable circumstances or time frames, i'm sure it happens all the time with slick salesmen and soecifiers who don't understand it but does it happen more often than not? I get that there are extra steps needed and it's much more involved but i'm not hearing that it's an unsuitable substrate to tile to point blank.

 

[The D]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Why is that Deano? Is it because you don't believe what you were told on the day and it didn't sit right with you? (as is you're well within your rights to do) or because you followed what you were taught and it still had a failure?




That's a different matter and that should be the specifier for the high jump if it has been specified in unsuitable circumstances or time frames, i'm sure it happens all the time with slick salesmen and soecifiers who don't understand it but does it happen more often than not? I get that there are extra steps needed and it's much more involved but i'm not hearing that it's an unsuitable substrate to tile to point blank.

Alan did an amassing job of making me understand what these screeds can do to cement based adhesives if the floor is not completely dry and thoroughly sanded and primed. How ever am I sanding to remove the laitance or just to prep the floor ???? I thought it was to remove the laitance but what do I know. I could get myself a fancy moisture test gadget to determine whether the floor is dry but if I do I will need to ignore the manufacturers instructions turn around three times and hop up and down on one leg and hope it gives me a correct reading as if it does not I will be in the frame as I ignored the manufacturers instructions . Then we have the debate epoxy primer or acrylic primer cement based adhesive or gypsum. I am convinced that acrylic primer and cement based adhesive does not give a strong enough bond as the tiles I have removed from the floors that I have fixed came up far to easily and my knowledge of gypsum adhesive is limited to what I have been told witch is very little. So you see I am no expert so how can I go and specify and guaranty a safe method of installation.

 

[Spud]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

when I sanded the last anhydrite floor I tiled I used a 9inch grinder with a 7inch diamond cup wheel with a dust extraction cowel 1500w dustex hoover with a preseperator, a slow speed machine might have been better but i am of the opinion the floor is not properly sanded until you can see the aggregate which why I used the grinder ,the floors take an age to dry here because our sites are far more open to the elements ,one of the last thing fitted on sites in the uk are the doors and windows until we build like the europeans we will keep getting problems with this type of screed Alan does have a good point too builders in germany have strict contracts which covers every detail so they is never a grey area on whose responsibiilty it is to do which part of the the job

 

[Ajax123]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

You don't need to sand low laitance screed till you see the aggregate. In fact this could be counterproductive as you can grind too much off and leave the screed too thin. I agree with your comment that a slower machine but with ideally a sixty grit paper. Worst case scenario is that a copper disk would be needed but this is not a common scenario. A slow 75 rpm 18" (ish) STR floor scarrifier is the right type of machine although last year I had a lot of success with enclosed shot blasting for larger floors. This works just as well. This is done tomsimply prepare the screed by removing extraneous construction debris as the screed does not for a laitance to speak of. if it does ther is something wrong and it should be batted straight back to the main contractor/builder and in turn presumably the screeder.

If it is a non low laitance screed sanding should be done before the screed is heated and this will easily remove the laitance. My opinion is that this is part of the screed installation and should be done by the screeder but as already stated this is a contractual matter and anyone can contract to do it if they want. That is not something that the screed manufacturer can control. As I say though this part should in my opinion be done by the screeder. This will expose a textured porous surface very similar in appearance to tha of a sand cement screed but generally much lighter in colour. Then just before tiling the screed will probably need a light abrasion to remove extraneous material as it will have got dirty and have a stuff dropped on it.

Sreeders generally dont like to sand off laitance and builders often don't plan their sites to allow for it in a timely manner. That is why there are so man failures on the old laitance screeds and as a result most of the anhydrite screeds that go into the market these days are the low laitance variety.

 

[Colour Republic]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

So let me understand this

if it's low laitance screed, you are only sanding to remove builders crap So say for example a screed was laid and no one went near it until it dried and there was no dust in the air, then technically you could tile straight on to it... with suitable adhesive.

If it's normal screed, then you need to sand it to remove laitance but ideally before the screed is heated, you'll then have to do another sand to remove builders crap if used before tiling?

 

[Colour Republic]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

Alan did an amassing job of making me understand what these screeds can do to cement based adhesives if the floor is not completely dry and thoroughly sanded and primed. How ever am I sanding to remove the laitance or just to prep the floor ???? I thought it was to remove the laitance but what do I know. I could get myself a fancy moisture test gadget to determine whether the floor is dry but if I do I will need to ignore the manufacturers instructions turn around three times and hop up and down on one leg and hope it gives me a correct reading as if it does not I will be in the frame as I ignored the manufacturers instructions . Then we have the debate epoxy primer or acrylic primer cement based adhesive or gypsum. I am convinced that acrylic primer and cement based adhesive does not give a strong enough bond as the tiles I have removed from the floors that I have fixed came up far to easily and my knowledge of gypsum adhesive is limited to what I have been told witch is very little. So you see I am no expert so how can I go and specify and guaranty a safe method of installation.

It seems on a busy site the hygrometer isn't a good method unless under armed guard 24/7 but there are other methods not prone to some idiot booting it across the floor.

Maybe this is one for Gary and 'co to do a test on with regards to compatable addys, or even yourself seeing as you started the whole ball rolling with these tests?

Alan does a sample section of screed have the same properties as a typical floor... i.e is there any reason why a 1mx1m sample wouldn't act like a large floor, in realtion to testing addys I mean?

 

[Ajax123]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

So let me understand this

if it's low laitance screed, you are only sanding to remove builders crap So say for example a screed was laid and no one went near it until it dried and there was no dust in the air, then technically you could tile straight on to it... with suitable adhesive.

If it's normal screed, then you need to sand it to remove laitance but ideally before the screed is heated, you'll then have to do another sand to remove builders crap if used before tiling?

Thats pretty much it although the low laitance may need a vaccuum cleaner running over it.

As a small example I Have low laitance screed in my own house and I placed smoothing compound (gypsum based) on it without testing for moisture, without sanding in any way and with only a light coat of acrylic primer diluted 3:1 ( think from memory it was BAL) that was about four years ago following a vac using the dyson. I Also stuck some ceramic tiles to it using creativeimpressions gypsum based adhesive. I left the tiles there for three weeks before tryin to take them up as I was laying laminate and not tiles. ( It was just my own test) The tiles would not come up without breaking and the adhesive wold not come away from the screed at all. I levelled over the adhesive residue after using the angle grinder to grind off as much as i cold. It is all still there and has even been wetted several times as I had a leaking roof. None of this has come apart. I know it works and is incredibly robust but professionally I am not allowed and will not condone cuttin corners.The reason get away with it is because I know how these things perform together cos that is my job.

ALL screeds should be sanded, vacuumed and moisture tested prior to fitting bonded floor coverings.

 

[bugs183]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

I'm doing my best Deano to come up with the answers we need:
As discussed Mapei have gypsum adhesives available on the continent, but not here. I phoned technical and they recommend Adesilex fixed to primed anhydrite with Eco Prim T or Primer, and have no news of importing their gypsum adhesive (very odd).
Bal give much the same spec with cement based adhesives.
From my small tests and from previous jobs i won't use cement based adhesives for direct fixing to Anhydrite.
I've tested a few Gypsum adhesives and yes they stick well to gypsum but not very well to porcelain, which is now in the majority for floor tiles.
In a few weeks i've a 60m2 floor and i've spec'd Creative Impressions GBTA adhesive. From what i've hear it's very impressive stuff so i'll test that against the others. I'm kinda feeling confidence that this will be the adhesive i've been after.
But it it fails then, we do know that gypsum adhesive sticks to gypsum, but also sticks well to Ditra, which i was surprised about. Fix this and go onto the ditra with cement based, it solves the cement to gypsum problem and the gypsum adhesive to porcelain debate, and when used with underfloor heating then this is going to be a good system as the Ditra absorbs any screed movement.
So all is not lost matey, we'll get there.

 

[Ajax123]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

It seems on a busy site the hygrometer isn't a good method unless under armed guard 24/7 but there are other methods not prone to some idiot booting it across the floor.

Maybe this is one for Gary and 'co to do a test on with regards to compatable addys, or even yourself seeing as you started the whole ball rolling with these tests?

Alan does a sample section of screed have the same properties as a typical floor... i.e is there any reason why a 1mx1m sample wouldn't act like a large floor, in realtion to testing addys I mean?

I have only ever seen two instances that I can remember where hygrometers were booted across the floor. Both were major hospital projects of several tens of thousand square meters. The simplest thing to do to prevent this is to mark it out as a test area with a bit of danger style tape and some cones or bits of wood or just put a bloody great kerb stone on topof it. stuff like this is available on most commercial sites. I often get this as a objection butin reality I do not beleive it happens often. On small sites it is not generally necessary.

there is no reason why a small sample will act differently to a large sample except obviously it is relative to the conditions it is kept in. In fact most of the adhesive company's test adhesives generally on much smaller samples I.e. 600mm x 600mm

 

[Gazzer]

Re: Anhydrite moisture testing, putting some ideas to you Trusted Peop

I would certainly be happier going the Ditra route but again more cost. I had enough trouble getting the job I am doing at the moment due to extra cost of Gypfix over a cement based adhesive.

As for the Hygrometer getting knocked about, I have had one trod on and another they swept all the other trades rubbish over it.....The Hygrometer was well protected and had a sticker on it saying do not remove, floor under test. You really cant believe the stupidity of some people.