Power Washing and Roof Cleaning Forum

Andy Hinson · Approved Exterior Cleaner

Slate roof cleaning question

waxman18324 · Founding Member Rest in Peace

Andy,

We do slate every year and the only difference in our procedures is that we don't use a surfactant. I don't believe they are harder but you'll have plenty of run off to contend with. If I find moss and or lichen we rinse the roof until it's gone. Either way we charge accordingly. I'm sure Eric and Lisa will weigh in on this as well.

Hank

Andy Hinson · Approved Exterior Cleaner

Thanks Hank. I thought I remembered seeing something about no Surfactant. Why is that?

waxman18324 · Founding Member Rest in Peace

I read it a few years back that it's better not to. The soap might dry on the slate and have an adverse effect if I remember correctly.

Hank

Maverick Contracting · Approved Exterior Cleaner

Actually the first job I did was slate and used S/H and water only with no results (85+ degrees) bumped up to straight 12%, still nothing.

Problem was flash evaporation and absolutely no runoff. This was a test situation so third step was to add surfactant for dwell time and BAM, instant results with no discoloration albeit did rinse. Since the hot slate evaporated the water (mix) no runoff.
$5k/5hrs plus tips, offered a $2k rebate
But he said no, deals a deal.

Every roof is unique so results may vary.
We do a lot of slate and is my preferred media 😊

-- Edited by Maverick Contracting on Tuesday 3rd of May 2016 07:10:55 AM

Liberty SoftWash · PWS Vender

We clean slate a lot of slate and just use SH and water.

Andy Hinson · Approved Exterior Cleaner

Thanks Guy's

-- Edited by Andy Hinson on Tuesday 3rd of May 2016 10:36:43 PM

Maverick Contracting · Approved Exterior Cleaner

I'm sure cooler Temps whereas the evaporation isn't as fast simple SH and h2o would be fine. Definitely gonna try as I have potentially a slate to do in a few weeks with some interior work so I'll do it on a cooler day. I just always use a little soap cause I hate going back and respraying. Lost time is my biggest annoyance.

BlueRidge · Approved Exterior Cleaner

We do a few every year and have always added surfactant. We cool the roof first then clean and rinse in sections. It has worked well with little run off. I charge more than double of asphalt.

Maverick Contracting · Approved Exterior Cleaner

True Brett, since it costs 10X to replace than asphalt!

Dan · Veteran Member

This has been the thread I've been hoping for!
I have a long-time window customer who needed a price on cleaning their slate roof. It's pretty mossy on 90% of it. The quote I gave was a bit, not drastically, higher that what I'd give for asphalt. The owner seemed floored at the price as he knew of other prices paid. I told him I'd do some research and make sure I was in line with my quote or needed to adjust it. Eventually, I said I felt I really should stick to my price and haven't heard back.
Maybe he's called you, Hank. It's on Lake Wallenpaupack.

waxman18324 · Founding Member Rest in Peace

Didn't hear from him.

Hank

Dan · Veteran Member

I certainly don't think you'd me much if any lower than me, so I'm not sure what they will do. Hopefully not hire a hack.

waxman18324 · Founding Member Rest in Peace

Dan wrote:
I certainly don't think you'd me much if any lower than me, so I'm not sure what they will do. Hopefully not hire a hack.

Anything is possible albeit a shame.

Hank

DirtyRoofcom · Approved Exterior Cleaner

I do my share- favorite roofing to clean. i dont see a difference with surfactant or not. just less runoff with it. I only rinse the lead or copper metals.

Heres one i did as the first job of the year. Just needed a nice rainfall to wash slates clean.

Andy Hinson · Approved Exterior Cleaner

DirtyRoofcom wrote:
I do my share- favorite roofing to clean. i dont see a difference with surfactant or not. just less runoff with it. I only rinse the lead or copper metals.

Heres one i did as the first job of the year. Just needed a nice rainfall to wash slates clean.

Wow! That's a great pic. I can't imagine cleaning that without some skicky stuff.

DirtyRoofcom · Approved Exterior Cleaner

Andy Hinson wrote:
DirtyRoofcom wrote:
I do my share- favorite roofing to clean. i dont see a difference with surfactant or not. just less runoff with it. I only rinse the lead or copper metals.

Heres one i did as the first job of the year. Just needed a nice rainfall to wash slates clean.
Wow! That's a great pic. I can't imagine cleaning that without some skicky stuff.

Ive been using it lately pretty much whatevers in the tank from previous roofs. this baby was steep!

Patrick G · Approved Exterior Cleaner

Soap is ok to use on slate......it was the alcohol that would leave a stain.................

DirtyRoofcom · Approved Exterior Cleaner

Patrick G wrote:
Soap is ok to use on slate......it was the alcohol that would leave a stain.................

are you drinking and cleaning?

Patrick G · Approved Exterior Cleaner

I thought everyone was?

Maverick Contracting · Approved Exterior Cleaner

The only problem I had with not using surfactant is in hot weather the chem. had no time to dwell, the SH would flash vaporize before it could do anything. I mean I even used straight SH as a test and it flashed off, as soon as I added surfactant for dwell it was magnificent how fast the slate cleaned up.

Admin · Head Quarters

Slate Roof Cleaning

-- Edited by Art O on Sunday 8th of January 2023 05:57:42 AM

DirtyRoofcom · Approved Exterior Cleaner

Slate roof cleaning

Admin · Head Quarters

Nice work Erik

BlueRidge · Approved Exterior Cleaner

DirtyRoofcom wrote:
Slate roof cleaning

Nice Erik! I don't know why some make it a big deal cleaning slate. It takes a little patience and a bit more time. Once clean, they look new!