[rb4no]

Afternoon, been asked if I can clean an original unpainted pebble dash wall. It has a lot of black organic matter, did a test patch and the mortar just sucked the solution in and the results were probably 30% where it needs to be. Anyone here have experience on these? I was thinking maybe a weak solution to saturate the substrate, then follow up with a stronger mix for the surface? Its a bit cold here so waiting on a warmer day to try out different ratios etc?

[Smudger]

Steam Clean

Darran

[Splash & dash]

We softwashing them with hypo mix give it a few coats leave if for an hour or so rinse with garden hose gently and over a few weeks it will come up like new I did my own house about 4 years ago and going to be doing it again in a few weeks not that it looks bad but just want to keep it algae free .  Biocides will also Do a similar  job but cost more , and take longer to get results .

[rb4no]

customer is hoping it will come up all golden like it did when new. i said you may get staining etc. i'm really reluctant to put any pressure on the wall as its unpainted and unsealed, it's 1930's original pebble dash and the whole house including indoors is like that, it's almost a museum to that era and the custy wants to keep it like that..

[Splash & dash]

customer is hoping it will come up all golden like it did when new. i said you may get staining etc. i'm really reluctant to put any pressure on the wall as its unpainted and unsealed, it's 1930's original pebble dash and the whole house including indoors is like that, it's almost a museum to that era and the custy wants to keep it like that..

In that case just soft wash with a hypo mix and then rinse with a spray from garden hose that won’t hurt it .

[Smudger]

Oh may have some carbonisation in there as it's pre war - hypo won't be enough you'll need different chemicals o get back to original

Darran

[chris scott]

15% SH diluted 4:1 with water add some Amine oxide to make it stick. Leave it for about 15 mins, rinse repeat 3 times. Thoroughly wash the wall leaving no trace of the SH. Then start with a 2% solution of HF acid mixed with Amine, wash repeat, if there is anything left it's on there for good.

[Yada Yada Yada - www.m-clean.uk]

If the OP knows what HF is, they may or may not - this is bad advice!!

Hydrofluoric acid (HF) is not something that should be promoted for use on a general cleaning forum.

Handled incorrectly it can cause serious injury to the operator (Injuries can be life changing, not immediately noticeable and with a strong risk of death) & may be sprayed onto others in the immediate vicinity.

From Wikipedia -

Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly corrosive. It is used to make most fluorine-containing compounds; examples include the commonly used pharmaceutical antidepressant medication fluoxetine (Prozac) and the material PTFE (Teflon). Elemental fluorine is produced from it. It is commonly used to etch glass and silicon wafers.

When hydrofluoric acid comes into contact with human skin it causes deep burns.

It is used to etch glass and in our industry for the removal of heavy carbon build up on stonework.

Extensive risk assessments & method statements should be carried out & followed to the absolute letter.

If anyone is thinking about using this chemical don't - unless you really know what you are doing.

I know you don't have much upstairs Christopher but try thinking before you type.

[Yada Yada Yada - www.m-clean.uk]

I'm hoping these photos won't be taken down by admin because they have been put up to show the effect of misuse.

HF may show no sign of skin damage but because of it's composition will attack the Calcium in your body (bones) and just starts eating them.







I've seen 1st hand an injury caused by this splashing someones stomach

[the king]

Agreed not to be messed with unless trained to use acids there was a chap on fb and his grand dad was using it on stone with no gloves or any ppe what so ever !! Absolute morons