[Blast Off Stoke]

can anyone give me some advice on any chems to clean a natural stone wall.I have cleaned stone before using just water and came up o.k. but was wondering if chems would make a better and easier job.
As far as i've seen its just general dirt on the stone and perhaps a few spots of lichen.
I dont normally do chems but this is a big job (for me) with a building contractor and i want to do as good a job as poss

[BDCS]

photos, photos, photos

[Blast Off Stoke]

sorry for the delay , just had new phone and still cant work the  thing !

http://img.photobucket.com/albums/v257/busterdog/DSC00018.jpg

http://img.photobucket.com/albums/v257/busterdog/DSC00015.jpg

[Matt Gibson]

Mayb try some hypo on it, but to me, it looks like theres a fair bit of carbon and stuff on there aswell. We used to use hydrofluoric acid to get that off the bricks, but it damages stone.

Try tensid.co.uk

they do all kinda of chems for all kinda of different applications. They have helped me out on a number of tough jobs. Im sure if you email them a pic, they will send you some samples of stuff they think will do the job.

otherwise you COULD try a small half a stone brick with hydrofluoric acid. Depending on where you are, it might be difficult to get. tensid sell it as heavy duty restoration cleaner.

Just do as many test with as many different things as you can.. and one with plain water, so you can compare. if the plain water brings it up almost as good as chems, just save yourself the hassle and use plain water.

Im sure someone else will be along soon to give you a better solution..

looks like a good job..

[BDCS]

I'd just use the bleach and then a quick rinse off with hot - it dos'nt look like there is anything too stubborn on there. I've been using chlorine tablets recently to good effect - just buy a tub and add as many as you need to water. Do a sample to guage the customers opinion

[Matt Gibson]

BDCS,

How do the chlorine tabs work? same kinda results as with the hypo? i guess it would basically be the same stuff wouldnt it?

[BDCS]

They used to be called bleach tablets - they brought a very black conservatory roof up like new last week but time will tell. They take up no room in the van, weigh nothing and are cheap.

[Blast Off Stoke]

Its in the middle of nowhere so should be  clear of most city grime .
I am tempted to try without chems first and see how it goes.
thanks for the tips.

[Kev Martin]

Always do a test area first so you know what you are dealing with both in materials and labour required.  This proves to the client you can meet their expectations and allows you to accurately prepare a quote. 

Method

Always pre wet the stone this ensures that the stone is saturated with water and not with chemicals. ( You want the chemicals to work on the surface).
Allow adequate dwell times (Too many people expect instant results).  Remember the dirt took 50 or 100 years to get in there don't expect to get it out in 10 seconds.
Finally try different things to clean it!  Sometimes an acid such as Aqua Mix Phosphoric Acid Substitute or Aqua Mix Extreme may work better than a high alkaline such as Aqua Mix Heavy Duty Tile & Grout Cleaner or vice versa.
Do a TEST area first

Kev Martin
Tiling logistics
Marble Life Ltd

[david_m]

Hi there

Another method of cleaning this stone wall, would be to sandblast it


 cheers  davy

[Blast Away]

Did this wall with HF last week. Don't know where damaging comes from, no damage here if you know what you're doing. Did the building in the background too but no after image yet as wanting to wait 'til it was dry and back there Friday to do the gable so will get one then.

[Matt Gibson]

I have used HF on stone before in central London with no probs but then not long after another guy in the company used it on another stone job and it stained the stone. After that I've always just been wary. But I'm not exactly sure what stone he used it on or what technique he used so it could b that he jus. Farked it up.   

[BDCS]

The trouble with these threads is that we can never guage the results from the different methods used. I have a soda blaster in the container and never get it out as I can usually get the results I need with chemicals

[Ashley Young]

Hi
We have used sand/water low pressure blasting of numerous stone buildings and the results have been great although it does take longer to clean up. Because of this i have started using different chemicals with mixed results. I would definately try a few different methods on test areas first to see what does the best job on your particular building.
Thanks
Ash

http://www.welcomehomesnortheast.co.uk/newcastle-cleaning-company