[Rob@Blast off]

How could I identify it? the customer didn't know what it was and I used a natural stone sealer as it is natural stone which gave the desired wet look that the customer wanted.
I'm happy and my customer is delighted with the results.

[Rob@Blast off]

I thought it was slate? I used ultra hd natural stone from sealers direct, very impressed with it and going to try there block paving sealer next.

The job looks really impressive. A real transformation!
 
We use impregnating sealers when we seal limestones and sandstones ...over time we think they last longer and course less problems than high solid sealers. If you are getting into sealers maybe it's something you should look at.
 Just something we have picked upon after trying different products on different surfaces.

Cheers Chris, what sealer would you recommend for block paving? As I have always avoided sealing up to now but after seeing the results I want to start pushing it more.

[Roger Oakley]

How could I identify it? the customer didn't know what it was and I used a natural stone sealer as it is natural stone which gave the desired wet look that the customer wanted.
I'm happy and my customer is delighted with the results.

May be some Research into different surfaces? but if your customer is happy then I guess that's what counts?

[drive surgeon]

Looks defo like limestone

[chris scott]

I would leave sealing block alone till next year...it takes 3/4 days of sunshine to dry out block enough to seal. Those days will now be few and far between.

[wpclean]

I would leave sealing block alone till next year...it takes 3/4 days of sunshine to dry out block enough to seal. Those days will now be few and far between.

Tell me about it 

[Simon@Pristine Pathways]

Perfect weather this, sealed 4 last week and got 3 to do this week. Hope it lasts got 5 more 25l to use up !

[Smudger]

Just a thought I'd bump this thread








Darran

[cleaning4usussex]

Looks really good 😃

[Smudger]

Thx there was a sandstone patio out back as well

Darran

[cleaning4usussex]

How long did that take you? Did you just turbo nozzles the lot or did you Fsc first then went over with turbo nozzle? Jamie

[Smudger]

Turbo nozzle

3.5 hrs - good water flow on site even at full power the tank was filling faster than we could use it

Darran

[Rob_Mac]

Darren

Good job there. I would have had to just take care of that 1st metre of wall and that sill.

Rob

[Smudger]

I did try rob honest ! Always like to go that little bit extra, but unfortunately I don't know what the black is, I tried hypo but as you can see it didn't really shift it, this is a converted school built in 1877 and unfortunately the brick is really soft and the window surround/sill is virtually crumbling away it has areas of errosion ( big flaked areas 3 to 4 mm deep ) and didn't feel confident that I could clean it up without further damage..

But I'll try harder next time 

Darran

[Rob_Mac]

No mate

It wasn't like that.

It looks like it's in really good order from that picture and if i'm honest I thought it was a newer building made to look older than it is.

That discolouration is coming off the sill so it must be something to do with the sandstone.

Rob

[Roger Oakley]

The discolouration might be that at some point there was metal window frames? so years of oxidisation from those maybe?

[Rob_Mac]

That front one looks like it still is mate. So probably the paintwork has been in disrepair, caused the problem and then it has been repainted but too late for not marking the stone.

Added - Darren I didn't see the loose stone underneath the brickwork but that is holding water and drawing up the brickwork as well and I would suspect that that side of the building doesn't get the main sunlight.

The fact that they have painted two cricket stumps on the wall tells me they don't see the value of the building. Just read some interesting articles on cause and effect of damage to stone that are a little bit bigger than the obvious.

Rob

[Smudger]

Rob, your correct on both counts the metal windows are still in ( this is the case on all the original parts of the school ) and the front North East facing.

Any links to the cause and effect ? Or are they old fashioned print articles

Darran

[trevor perry]

very easy to remove that staining the only trouble being is that the rest of the building would then look dirty as the area cleaned would be brighter than the rest

[chris scott]

Need a better pictures really BUT AT A guess Carbonation of sandstone followed by freeze thaw.
Can be cleaned with caustic liquor ,neutralised with an acidic wash.
The wrong thing to do would be to clean it with a pressure washer... the glass has acted as a catchment area and  caused the problem.