How to Clean and Prevent a Mossy Roof | Ask This Old House
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- Опубліковано 9 лют 2020
- Ask This Old House general contractor Tom Silva helps a homeowner remove moss from his roof and prevent it from growing back.
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Time: 2-3 hours
Cost: $100
Skill Level: Difficult
Tools:
Safety harness system [amzn.to/2H2hhEC]
Push broom [amzn.to/384lpQh]
Hammer [amzn.to/31Dzi5S]
Caulking gun [amzn.to/2OyLLlN]
Garden hose [amzn.to/2usm27I]
Rubber gloves [amzn.to/3baakiG]
Shopping List:
Zinc strip [amzn.to/2Sk9asm]
Roofing nails [amzn.to/39hNdRp]
Roofing cement [amzn.to/2Hcyonz]
Pump sprayer [amzn.to/2OyBIgA]
Bleach [amzn.to/3bffNEY]
Steps:
1. Start by securing the harness system to the roof, following the manufacturer’s instructions to ensure they’re installed properly.
2. Using the push broom, lightly sweep the roof to get off as much of the loose moss as possible.
3. Install a zinc strip near the ridge of the roof. When it rains, water will pick up the particulates in the zinc and deposit them along the roof, preventing more moss from growing.
a. Roll out the zinc strip underneath a course of shingles, allowing roughly half of it to be exposed and the other half underneath the shingles.
b. Nail roofing nails about halfway through the zinc strip, just to get it held in place.
c. Apply a bead of roofing cement around each nail before nailing them all the way through. This will help seal up the hole made by driving the nail.
d. Once the nail is all the way through, add another bead of roofing cement on top of the nail.
e. Repeat this process for all the nails.
4. Below the roof, spray any plants or grass with water to protect them from any runoff bleach that may fall off the roof during the next steps.
5. In the pump sprayer, pour a mixture of roughly 1/3 a gallon of bleach to 1½ gallons of water.
6. Spray the bleach mixture on the roof. The bleach will kill off any leftover moss over the next couple of days.
7. Remove the harness system from the roof.
8. Spray any plants and grass underneath the roof with water again once the process is completed.
Resources:
When working on a roof, safety is very important. Tom added a roof anchor [amzn.to/2S3D991] to the rafters, wore a harness, and used a safety line [amzn.to/2OzVZCx]. These can be purchased at home centers or hardware stores.
Tom used a push broom to gently remove the loose pieces of moss.
He then installed a roll of zinc strip moss preventer, which can be purchased online or at specialty retailers.
Finally, he sprayed down the roof using a solution of water and bleach. He started at the bottom of the roof and worked up so that he wouldn’t step on wet areas and slip.
About Ask This Old House TV:
Homeowners have a virtual truckload of questions for us on smaller projects, and we're ready to answer. Ask This Old House solves the steady stream of home improvement problems faced by our viewers-and we make house calls! Ask This Old House features some familiar faces from This Old House, including Kevin O'Connor, general contractor Tom Silva, plumbing and heating expert Richard Trethewey, and landscape contractor Roger Cook.
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Keywords:
This Old House, Ask This Old House, DIY, Home Improvement, DIY Ideas, Renovation, Renovation Ideas, How To Fix, How To Install, How To Build, Tom Silva, roof, moss, cleaning, prevention
Watch the full episode:
www.thisoldhouse.com/season-1...
How to Clean and Prevent a Mossy Roof | Ask This Old House
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“I listen by sound”......brilliant!!!
So do I ;)
If you feel by sound, you need ear defenders on ;)
pmailkeey synesthesia can be wonderful
I smell by sound
I had the same problem and swept across the shingle edges with a straw broom. I used a beach solution as well. I thought there is a better way. Seeing this pro do pretty much the same,I feel better. Thank you Tommy and TOH.
Have been a viewer since Bob Villa and before he was gray! Have always loved learning repair and restoration by "best practices". It honors the home through developing craft. Thanks to all you gentlemen through the years for a great and continuing, quality show!
I am not a Home Owner "yet". But me and my wife are in the process of purchasing our first home in the near future. I saw this episode. And it will give me a heads up on a Mossy Roof.
Thank you to This Old House And You Tube 😀
In my 40 years as a roofer I have never seen moss and the additional moisture it collects make water proof composition shingles water permeable. Moss can hold moisture at the butt of the shingle close to the nailing line, and so close to nails. If the moisture is salty and the nails are not hot dip galvanized, copper, or stainless steel they may rust out. There are indications that some moss inhibiting treatments are caustic to the nails. In general moss growth on a composition shingle roof that is fastened with quality nails is an appearance issue. The sun's UV rays are the main source of composition shingle damage. The north face of a roof may look shabby, but the south face though looking fine from the ground, could be weaping due to lost surfacing, vaporized asphalt, and exposed fiberglass mat.
I noticed my garage roof has green moss on comp shingle butts under trees an a north facing side. IIRC 19 years ago when I stripped the old roof I never saw any real evidence of degradation in that area. I might add that the roof was at least 25 years old and still watertight, roofs last forever in my mild (40-70 degree) climate on the California coast, but since I was doing the house we went ahead and did it all. Do you think the safest bet is to just leave it alone unless it sweeps off? BTW I get the moss mostly from the fog making the trees "rain". I might add I am far enough from the ocean that I can get away with galvanized flashing.
@@monshes Sounds like you might be a neighbor. I'm in the Eureka, Arcata area of the California coast. Anyway I have not seen any functional benefit from moss removal. Loose debris and some moss can be removed with a blower, which is less abrasive than brooming. Appearance is a fair consideration in some cases, but moss removal does not promote or increase roof longevity in my experience. I have torn off a section of roof that was fully covered by a flat moss, like a carpet, but found no leaking issue, or water damage. Count the cost of roof maintenance, in time, in money, in effort, and possible danger. Remember even good roofs, properly applied, do wear out, and new ones cost a bunch. My idea is to only do maintenance that will forstall replacement. That would mostly be keeping the loose debris off, and trees/shrubs from overhanging and/or rubbing on the roof. Chimney, and skylight collars should be monitored, and prepped and painted as necessary. Plumbing vent seals, where pipes pass through the cone of the base flashing should be renewed as necessary. I have only seen moss be a contributing factor the one time in 40 plus years, so without further evidence, I believe the worry about moss damaging composition shingle roofs is much overblown, and causes unproductive, possiblely destructive, efforts. Good luck.
The only reason I needed to do this was because Farmers Insurance would not insure my home unless I removed all the moss. And is was minimal moss on a roof with no trees over it and not shaded by any trees!
@@monshesu
You're always the man Tom. U really know your stuff.
"It's supposed to" lol
Ranks right up there with "Oops!" and "UHHHHHHH,hide!!!!!" LOL
"it's supposed to" is code for "I don't know, never tried it".
It's a three word disclaimer. lol
It's supposed to...
Translated:
TBH I dunno.
I'm watching everything you all put out about roofing because some shingles blew off during a storm and this video answered all my questions about the safety harness! Could you make a video about all that outside of the moss removal video? Love your show!
I'd give anything to have Tommy "the legend" Silva come to my home and help me with a project. I'd even film it for posterity sake. These guys are the GOAT of HI. Grew up watching them and I always will - in reruns!
As a home inspector, videos like this are great for educating my clients. Thank you so much
That’s not really a great method of doing that roof. Soft washing would have been the best way use chemicals and light water. By first sweeping it you’re losing all of the granules. And now we’re hammering more nails into the roof for something that might work
Yep. I was cringing seeing him face nail that zinc strip. I'd never face nail metal on a shingle roof. When that roof contracts in the winter, that's going to open up. If they really wanted to self-seal the nails, they could've laid down a strip of ice & water shield first then lay the zinc over that. But even then, I'd never rely on that to keep moss off the roof.
I'd just give that roof a wash down every few years as needed.
But then again, I'm a roofer. ☺
Not sure if you've covered this before, but screwing a bracket to a rafter through the roofing is a penetration. How do you deal with that? HOW GREAT! You actually covered it at the end. This is the first video I've ever watched where they talked about a harness and then followed up on what to do after removal. Thank you:)
Seal.
I had this issue not as advanced. I used Wet & Forget Outdoor Algae remover, Except applied with 1 gallon bug sprayer. No harm to shingles. No rinsing off. Worked great. Read bleech can discolor shingles.
Good to see tom still climbing houses
Homeowner is sweeping that roof like it owes him money
I have A LOT of moss on the roof of my shed/shop here in CT. I put in a wood burning stove a little while back and used galvanized pipe to secure the stove pipe to the roof. There are two perfectly clean strips running down the roof starting where the galv pipe is secured. Now, the moss free strips don't run down all the way to the gutter, but maybe 6' down. And the galv pipe is an old soccer goal post and it's, what I'd say, heavily galvanized. I think if I'm going to do this zinc strip thing I'd want to find galvanized strips that are more heavily coated than the stuff they're doing in the video. The concept DOES work though, and that's cool.
Also, a quick note on roof harnesses. The Workman's Comp insurance premium for Clerical workers is 12 cents per $100 in payroll. The Workmans Comp Insurance premium for roofers can be over $50 per $100 in payroll. QED...
Very thorough and well done job!
Grew up being FORCED to watch this show back in the Norm Abram days... didn't realize how beneficial it would be back then lol
The accent brings me back.
Love all of you guys.--Great job on everything you do.
I like this channel, very profession experienced people sharing their wisdom with us
This dude , he actually listens by sound!
Incredible!
helpful video. I've been a climbing instructor for over 25 years. it might be helpful to mention that bleach on your rope and harness will degrade the material and shorten the usable life span and weaken the rope. If you do get bleach on your rope, rinsing the rope will help. the worst case would be repeated exposure to bleach without any cleaning. I hope this info helps somebody out there stay safe on their roof
Wow that’s awesome video I’ve been looking for a visor like this good job guys
My brother just moved (in January) to the Eugene, OR, area. He said that many roofs there (at least, in his neighborhood) have moss growing on them.
Would you kindly show a followup "After" video over the next month - 3 month - 6 month time frame to show hoe effective this is over time? Thanks a lot!
I've sent other videos where it shows the strips of zinc are only effective for about 5 rows of roof. So some people install the zinc every 4-5 feet.
@@lbatemon1158 I used copper strips with uncertain results. I recently found out some shingle manufactures are including copper granules in the crushed shale surface. Lastly, I used a product originating in New Zealand called "Wet it and Forget it." Between the roof spray and the copper, I got good results on both the lichens/algae and the moss.
I have used a product called wet and forget for moss, It worked very well.
Tim Walker Same here. It also prevents regrow the for about 3 years. Initially it makes it look worse then it gradually removes it. Great stuff for sure
Hi TOH dudes, you can slip some flat metal/coil stock up in under them shingles when you're done with the brackets too, no caulk or you can caulk too.
Excellent segment thank you
Great video, I am going to try a copper strip and see how that works.
If you still want an old house listen to this guy LOL. Blanchard Vancouver
such as all wooden houses from the states , they are not going to last long, also I can see that the roof is not made for lasting more then a couple of years , so maintenance is very important here, I like very well the expert who is explaining how to fix everything , the way he explain is is really great , nice to see that he is a real expert .
Thanks for the info Tawm
On my house, due to a walk out basement, the back of the house is 3 stories up. When I work back there, I put on a harness and I run the rope over the peak to the hitch of my truck parked on the front side of the house. It takes pretty careful measuring to make sure that, with the length of the rope, the truck is positioned correctly to not allow me to hit the ground. Better than putting nails through the shingles.
@@TPSBoston Not likely when it's not a "jobsite", but my house and I have the keys.
Thank GOD for that safety harness!
I installed zinc plates along the ridge line of a new roof 6 years ago. Last year I saw that isn't adequate. I resumed treatment with "Wet and Forget". This is the right supplement to the zinc.
Gordon Adams string, and fasten on each end a permanent copper wire across the top shingle and forget
John Budd does this work better than the zinc? I have a friend who did the zinc strip and still had moss 2 years hence. (And copper’s easy for me)
jasonji1900 never tried Zinc. I have used copper.
Thank guy fr yet another educational video
I use a rope system all the way across the roof, ground weight to gutter to Crest to opposite gutter to ground weight. No need to nail anything . Works on metal roofs therefore also.
I have a moss issue! Thank you..
Great video as always, wealth of info
Like belaying when mountain climbing wrap rope around waist left to right,keeping rope in hands if rope slips u press down on thigh stopping fall.
Use "Wet it and Forget it". Mix as directions. Spray on dry roof only and leave it. It will turn the moss Yellow and later it will wash off with the rain. No rinsing or brushing and it will not kill your plants when it runs off roof. Best product I have ever used for moss.
Agree
Does it work for the actual moss? Not just stains? I have a layer of moss on my roof but don’t want to go on the roof
@@cliff9685 If mixed as directed with water and applied on dry moss it will turn the moss yellow and it will eventually wash off the roof under heavy rain.
@@stevehudson4151 thanks! I’m looking at the xtreem reach one that hooks onto garden hose. How long does it take to work and fall off?
@@cliff9685 It is a slow process and depends on the amount of heavy rain you have after it has turned yellow which I have found is within 2 weeks. This is the only option I have found to remove moss without a roof damaging invasive process.
I have no reason to watch this video other than listening to Tommy’s New England accent. Number one preventive step for a homesick Rhode Islander.
Tom is an amazing dude
I like this program because I learn a lot, and Tomy reminds me of my grandfather
good info, didnt realize you could use less expensive zinc
Best "How To" show ever!
Tom I spoken with lots of roofers some say zinc strips copper strips help prevent moss growth, others say no and the reason is this metal strip may protect 5' of the roof but to be effective you would need to install several strips going down the roof to have any effect of moss growth.
Thank you
Very handy information.
I installed a zinc strip on my brand new shingle roof 3 years ago, moss is now starting to grow again and I live in vancouver, washington where it rains a lot so i will go back up and spray bleach on it again however i will use a stronger mix than you mentioned.
I’d love to get your feedback on the results of that zinc strip, please.
Love you Tommy!
I've been watching Spencer clays who deals with moss on roofs. Wanted to see how much difference Tom was in dealing with the problem.
Love everything great information. Other than the fact that you recommended using lead. Very scary solid metal there too much gets into your ground water. If you don't have well water it's soaking in the ground and then soaking in your pipes and coming back up. So I'm good on that. I'll go with the copper. Or the zinc
He did NOT "recommend" using lead. He was explaining the process how the metal prevents moss growth and mentioned other types of metals that WOULD do the same thing. Obviously the type he recommends is the type he used.
I wonder if you could do something similar to keep mold and mildew from uglying up your vinyl siding???
Oh. Well that seems simple enough. Thanks!
Great video, very informative. Do you have more roof cleaning related videos?
While somewhat worthy of your time & effort it's something I cannot ever fathom doing. If that were my biggest piece of the puzzle to land I would be clicking my heels !
I'm not a big fan of trees overhanging a house. Seen way too many roofs wrecked.
One time was working on a house that had a pine tree overhanging the attached garage. The roof was so wet that we had to replace a huge section of the decking too.
Nice work.
spread sunlight powder detergent over top of roof, works in Vancouver,bc
Safety is #1 priority
could you leave the bracket up on the roof and seal the holes before you screw them in???
Very helpful.
For a quicker clean, you can fill a pump up sprayer with some pool shock found at a local pool supplier. Dilute that at about 5:1 and spray on the roof. Let that sit for about 20 minutes and use a garden hose with a strong nozzle to rinse off. You will likely be able to avoid going on the roof entirely unless you want to install the metal strip.
5 parts shock one part water or other way
@@tylersawyer9837 I typically use about 15-20% shock. The rest water. But, I increase depending on how much stuff is on the roof. It dies pretty quick and the next rain will typically wash it away.
It's quite amusing that we had the opportunity to clean several moss-covered roofs in the Seattle, WA area, and interestingly enough, those roofs had zinc strips just like the ones shown in this video.
Tom Silva it’s great , it will be hard to see him go
I didn’t know I had a fear until I trimmed the sheeting on my roof when I built...standing 20 feet in the air and my knees started knocking
I helped a friend of mine put up a metal roof and with each nail, we placed a rubber washer on the nail to ensure a water-tight fit. can one do that also or was that putty you used a better solution? DID you all revisit this roof to see if this technique really worked? I see people scattering a zinc powder (tide detergent) on the roof and let the rain rinse and spread the product. Any ideas about that? Thanks
excellent man
I spend the money and get a tube of Through the Roof. You can put a shingle down permanently even on a wet roof. On a new roof, the face nails, I seal then grab some loose roof grit and drop in the sealant to help hide it.
One thing tom. Didn't mention. Is that the pros recommend to put a zinc strip on I believe it's every 6th row or every 6 feet.
Wet n forget product works great👍👍
Tommy is the BEST !!!!!!!!!!!!
I also add Dawn dish soap to my chlorox/water mix to help the water be a better surfactant. I use a container with my solution that attaches to the end of my garden hose, not too harsh, to blow off moss instead of the aggressive scrubbing action they did. PS, I've worked on roofs for years and I've never installed a safety harness. Proper shoes and care, and you'll be fine.
I read elsewhere that using a detergent like dawn is not advised because it breaks down the shingles.
@@aLionhunts so far, my shingles look fine. No signs of deterioration. I bought the type that are 50-year rated.
interesting with installing that zinc strip !! thumbs up ....this is what I need to do ...
Yes, I need the same. Where can you get the roll
@@dennismurray8875 ...Ace hardware has 50 ft rolls ....Home depot also has it ... I bought and installed it couple weeks back after clearing my roof of moss...I won't know results for a yr probably....good luck !!
I actually have several permanent attach points on my roof that remain in place across the ridge.
@Mike Clarke: are the attach / anchor points exposed to the elements, or tucked in underneath the roof tiles? My tiles are glued down front and back - to keep out driving rain in the winter up here in the hills - and I'd have to pry them up; besides which they are rigid and thick, and not like the ones I see in many videos. Last thing: I have a vented ridge-line that is tall and even though I am light (150lbs) I expect it would collapse or buckle were I to have a rope thrown over it with my weight attached... so I'm thinking that I need 2 sets of attach points, one on each side of the ridge-line, which is a pain. (The v-shaped anchor shown here would not be flush with each side of the roof due to the pronounced height of the vented ridge.)
Good man! Since I started rooftop work, I've realized that what you've done, permanent ridge attachment points, should have been the first building code requirement ever. Roof work would be a lot safer for a legion of workers.
And who thinks it's a reasonable idea to put a bunch of holes in a roof every time you need to go onto the roof?
There would be a ton of easily water sealed attachment point designs developed by now, and techniques to utilize the ridge loops to get from gutter to ridge without a typical roof hook ladder.
After watching this video I realized a permanent attach as well!
I use a 50% bleach mix. Apply on an overcast day so it doesn't evaporate away. When the moss turns brown it is dead and can be swept away. I don't recommend power-washers when the force can knock you off balance like on roofs or from ladders..
Question: What is the most practical (cost benefit) gauge and width for the copper strips? I know that generally speaking the more material the better chance that it will leach and prevent moss growth; but there is a point that it's also an "overkill", particularly when considering the cost of copper; so, I am looking for cost benefit. I will likely do a strip every 6 feet, but am not sure if 24 gauge is best/needed, and 2" wide might not be enough material? Am using it on a north facing roof in a house in the PNW, specifically in the Puget Sound in WA state, and unfortunately the next door neighbors have messy trees... I blow the leaves/fir needles off the roof 3 - 4 times a year... but still need moss prevention mostly on the shaded side..
a recent article says put zinc tape along the top of the roof peaks. when the rain hits the zink, the zink minerals rolls off the roof and kills the moss
Philip DeArteaga if you watch the video they say demonstrate it lol
Amazon baby! Just look up copper powder made from pure copper.
Sprinkle on the ridges and top edges of the roof on the first rake of shingles where they meet the vertical walls of multi-story.
Zinc is okay. Copper has a much stronger effect and will keep the roof from staining, zinc will still allow the shingles to darken.
Anyone like me that has battled moss on the roof in Oregon...... knows zinc strips on the ridge is your best friend. But that strip alone is not enough, you buy a granular moss killer and toss that down on a regular basis, say twice a year.
What is the lifespan of the zinc strip ? Any opinion on the product "Wet and Forget" ? Thanks !
Tree huggers gotta love it. Use metal roofing screws no tar needed.
Backing soda works too.
I've never had much luck with zinc strips but here in Seattle, we have supermoss.
Live across the sound from you and I can verify the truth of supermoss :-)
Doesn't do much here in Tacoma
Sequim is pretty bad with moss
Southeast AK is even worse…
Funny I was just typing about using copper and they mentioned it. It is to do with acidity. The avid levels on a roof are higher. The copper runoff provides a neutralizer rhat assists in preventing the moss
Amazing
Wet & Forget Solution works great to get rid of Moss on Roofs and Wood Fences 👍🏻
My Suburu power washer would easily blow the composite shingles right off of the roof. I used the zinc strip as shown here. It definitely did not work. What did work was straight, full strength bleach sprayed on the roof.
Won't you void roof warranties if you nail the metal strip to it ?
I had a bad moss problem with moss bubbles 1 inch thick. I used a product called Roof Wash from Wash Safe Industries. I made one application, and the moss was gone in one week.
I’d love to hear a status update from you
This was a perfect video
But Tommy, what if you have to climb on your roof every year to sweep out the valleys of pine needles? I can't screw holes every year into the roof to reinstall the bracket and then caulk it or it will look like swiss cheese or chicken pox. Painting the bracket so it blends in with the roof color and caulking around the 12 screws in the same way as you sealed the nails on the zinc strip and leaving it permanently up on the ridge makes sense but it leaves it exposed to rain and rusting in the hinge or O-ring. I've been attaching my line instead, over the ridge to my pergola on the other side of the house. I lay tarp down along the ridge so the line is protected from abrasion as it slides along the ridge when I'm walking back and forth on the roof. The pergola is a massive timber frame structure and the 6x6 timber I'm attaching my line to is lag screwed in with mutiple sizable screws so the shear strength should withstand my 140lbs.
He has moss & he's not lichen it.
john w oh! I see what you did there... that's funny.
john w Boooooo! Lol; that was funny!
Bahahaha
Boooooooo
Hahahahhahaha
They actually have roofing nails with a rubber seal around them. Much easier.
And not nearly as good
Do you have to place a zinc strip on both sides of the roof?
Can you use gasket head nails instead of roofing nails and tar?
So what happens when you need to go up on the roof again, which most do at times. You have to keep making all those holes in the roof to support the bracket or can you keep using the same holes you made and keep filling in with roof cement? I would think re-opening the holes all the time would weaken the shingle. Any comment on this. thanks.
I tie-off to a tree or park the truck next to the house and tie-off to hitch bar or solid bumper, never poke more holes in your roof.
I love the show
I learn a lot on show
Good one