Is Spray-on Roof Coating a Con?

Martin asked Skill Builder:

Some years ago a company put flyers through all the letter boxes for cleaning and painting roof tiles.

They claimed it would improve waterproofing. This seemed like a lie to me since the houses were built in the late 60s early 70s with concrete tiles over roofing underlay.

I believe the underlay is the waterproofing layer and the tiles are weather protection for the underlay.

At least two neighbours had their roofs done and one has since had the treatment repeated.

In the cavity wall video, you were asking for rant subjects and I do not recall seeing one on this subject.

The current roofing underlay is bitumen and loosely woven fabric that has become brittle and at least one house has had to have all of the roof stripped down and rebuilt because of it starting to fail.

I suspect some of the wood tile laths are also starting to get old and will soon need replacing.

The workers who did the work took no precautions for working at height, the properties are bungalows but the apex of the roof is at least 6m high. Gable ends no hips.

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#roofing #rooftiles #scamalert

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[DanielSMatthews]

We have those scammers in Australia too, I always figured that the guys stomping around on the roof were a bigger threat to its integrity than a bit of moss.

[danstrike]

My mums old house was a slate roof with no felt. It's still the same now. Well over 100 yrs old. Amazing really.

[American-In-Mykolaiv]

Thanks for the straight talk. I actually believe that moss on the roof tiles adds value - gives it the "living" natural look. It certainly does not degrade the roof's ability to keep rain out.

[alexscott]

Just like to add my two cents as someone who does a little bit of roof moss removal.

I think roof coatings, especially the ones that came about maybe 10 years ago are a bit of a scam/pointless. However, I do a bit of moss removal and then put a biocide (not a coating) application onto the roof which helps inhibit future growth. In theory, you can keep applying biocide every few years (fairly cheap to do) and it'll prevent any moss/algae/biofilm regrowth etc.

Certainly not every roof needs this, not even the majority of roofs need this. But there are obviously properties in troublesome areas (say in dark/humid areas under trees/lots of shade perfect environment to grow loads of moss and algae) that attention needs to be paid to those roofs. Also of course you can just opt to have moss removed for the pure curb appeal aspect.

I have seen one roof that was so thick with moss that it had added such a weight to the roof (imagine how heavy it is after a heavy downpour of rain or in winter when it'll freeze and expand) that it caused significant bowing in the roof and cracked some of the wooden supports underneath.

[abrandals]

You can also get a clear roof coating too. When applied, has a blue tinge to it but drys clear with a slight shine to it.

[paulhotson]

Using a high powered pressure washer could cause more damage than good, because the strength of the water stream can remove the finish of the roof tiles and increase moss to grow more in the future.

[MrThebigredone]

Roger, I live in Germany and last year in February we had a very fine snow that blew in under the tiles, old house with no felt of course.Didn't know anything until the drips started, in every room.I had to pull every ceiling down and re-do the lot.

Insurance assessor refused payout on the grounds that the roof was defective, ended up forking out 35 grand to have a completely new roof done...moral of the story?---easier to install felt than replacing ceilings and redecorating an entire house.

[tinysmallfryskitchen]

This happened to my parents, their clean roof seemed to be a bat signal to every con artist. Next they had someone come round and and jet wash their block paving, and spray it with a special coating that they said needed to be done every year.

[paultant]

Over here in the west of Ireland have seen a few roofs powerwashed and a special paint put on. Yes they look good for a year or so then back to old looking.

[pigswillbepigs]

Ps when they are up there break a few tiles, siliconed together, more damage than pre work.

[surfinchemist]

I've got over a decade of surface chemistry experience. Did extensive research on hydrophobic coatings and a bit with antifouling (stop barnacle growths on ships, moss/mold on wood) coatings as well. This is a con. Like rainex on your windshield any repellency effects will diminish rather quickly. Even quicker on roofing tiles given their friability, roughness, and porosity vs glass.

[njuham]

This summer I did replace some Marley Moderns from 1970, 25 tiles or so, the sides/seams were very badly eroded, crumbling away, not quite enough for water to get in but almost. I suspect the moss which has been freezing and thawing over the years.

[jasonantigua]

Hello boys, hope all you guys had a lovely day! Thanks Richard.

[rufus_mcdufus]

My dad had a visit from some travelling gentlemen a couple of years ago offering to spray the roof. He's rather gullible (and in his 90s) and was just about to hand over 1500 quid or so. Fortunately neighbours intervened and got rid of them, and in fact the police were involved too as these gentlemen were well-known to them. Of course I suspect 1500 quid would have just been the start of it.

[johnantonine]

100years for a concrete roof tile ? Have a word with yourself that's bad advice. 25-40 year old concrete tiles that are becoming porous will soak up water causing dampness, causing batten to rot, causing felt to deteriorate and putting alot of weight on your not so healthy roof.

If there is actually a coating that can seal porous tiles? It could probably get someone a few extra years of roof life until they get round or can afford a reroof.

The Marley concrete tiles they are producing the now are dud out the pallet never mind 100 years.

[fluffybadger]

I was quoted for the roof cleaning & treatment, I can't recall how much it was & the guy said it would be much more expensive for a new roof giving some silly price as an example. After doing a bit of research it actually wasn't that much more to have a new roof, plus it would last a good 50 to 75 years more.

[dougfranco]

fti did roof cleaning in Orlando FL for many years.. Chlorine and some water is what is used to kill all green or gray things for a year or two.

[chrisshattock]

In Spain: I would say two things - terracotta tiles and the mortar mixture used to bed them together. I am of the opinion that products like those of Sika are likely beneficial to their look and longevity - more as a method of "touching-up" tiles that have already largely been in place for 40 years. The biggest issue is "roof repairers" using an in-appropriate cement mixture which results in the rapid degradation of the mortar. For that I would be more inclined now to use a PU adhesive foam.

[stefanghiata]

Such an insipration, Roger! Thank you for your contributions.

[steveshephard]

As someone who repairs and restores old roof for a living, Paint is a protective coating that protects the substrate for further deterioration. If you don't maintain the roof of your home eventually it will cost you a lot of money when it needs replacing. Not only that but if you don't maintain your roof and need to make a claim through your insurance due to storm damage the claim will not be excepted by your insurance company.