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Algae appearing on all external walls

  • 07-03-2009 1:22pm
    #1
    Registered Users Posts: 1,013 ✭✭✭


    Hi guys,

    I'm having rouble with algae appearing on all external walls around my house. Last yr I had a similar problem so hired a power washer and got rid of the lot. However, since the new yr its returning worse than ever. I have algae on all external walls, front, back, garage and house and was looking for help in how best to clean it and ensuring that its not something that comes back again next yr.

    I was thinking that trimming the evergreen trees to the side of the house would be the first thing to do, then spray the walls with bleach, leave for a week or so, then powerwash the lot before painting with external wall paint.

    I suppose I need to get some experiences or knowledge of others who have dealt with this issue and is the approach above (however timely) worth all the effort or will it be back again next yr.

    Also, is there a particular paint I should be looking to use ?

    All help appreciated. Thanks.


Comments

  • Subscribers Posts: 40,732 ✭✭✭✭sydthebeat


    do you have sand and cement rendered walls, that are unpainted???

    what colour algae?? green or red??

    do you live in the midlands?? or near boggy areas??


  • Registered Users Posts: 1,013 ✭✭✭Curious Geroge


    Painted stone walls but I only ever started to suffer green algae last year and its continued this year. I'm based in co galway with no bogs or alike.. Cant come up with any reason other than the everygreen trees for the green algae but then again, they've been there for yrs too and i never had this issue before. I see it appearing on the garage roof now to sure its everywhere outside now and its horrid to look at..


  • Subscribers Posts: 40,732 ✭✭✭✭sydthebeat


    Painted stone walls but I only ever started to suffer green algae last year and its continued this year. I'm based in co galway with no bogs or alike.. Cant come up with any reason other than the everygreen trees for the green algae but then again, they've been there for yrs too and i never had this issue before. I see it appearing on the garage roof now to sure its everywhere outside now and its horrid to look at..

    powerwashing will never work to gid rid of this stuff...

    it must be treated with an algaecide (chemical treatement0 according to the product specification....

    this 'dead' algae must them be cleaned off with wirebrushes, and the result powerwashed.

    then paint over with a high-end external weatherproofing paint... id suggest Dulex Weathershield EasySpray Smooth Masonry Pain


  • Registered Users Posts: 1,002 ✭✭✭MargeS


    I have a similar problem. The back and side of our semi face north, north/west. The cement paths, steps and patio are covered with green algae. It makes for very slippery conditions when it's wet. Not to mention, it is so ugly!


  • Closed Accounts Posts: 14,144 ✭✭✭✭Cicero


    Painted stone walls but I only ever started to suffer green algae last year and its continued this year. I'm based in co galway with no bogs or alike.. Cant come up with any reason other than the everygreen trees for the green algae but then again, they've been there for yrs too and i never had this issue before. I see it appearing on the garage roof now to sure its everywhere outside now and its horrid to look at..

    Would be very helpful if you could upload a picture so an expert could give an opinion...there's algae, moss, mildew, fungus etc etc, so important to ID exactly what the growths are- --if you feel it's the trees, if some of the trees scyamores (I know these aren't evergreen but they do 'weep' leaving a sticky residue (especially in wet humid summers like the last 2 years) which can lead to algae growths-(large pine trees or similar in humid conditions can have the same effect) especially since you mention that the algae is on the roof, which is different than just mildew/fungus problems on cement walls - on the roof (especially on north facing houses) the effect can be compounded by poor insulation, leading to heat excape, which forms a perfect environment for algae/moss growth)
    Also, if the house is only a few years old, then check the following- ID where the algae growth is most apparent- if its on the North face of the house, then on going management of it will be required- the sun doesn't shine for long on the North aspect of the house (only partially), and couple that with the last 2 summers, you are going to get algae, moss and other such growths..have a small bit myself--even on the plastic gutters so for me, its a regular cleaning job every couple of years-
    Post a couple of picures and you should get a solution quite quickly-


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  • Closed Accounts Posts: 14,144 ✭✭✭✭Cicero


    MargeS wrote: »
    I have a similar problem. The back and side of our semi face north, north/west. The cement paths, steps and patio are covered with green algae. It makes for very slippery conditions when it's wet. Not to mention, it is so ugly!

    Just wondering what you have tried...from experience, this is normal (grew up in a house with a small North facing patch to the side of the house,.. the paths at that particular side required very regular (every 2-3 months or so depending) disinfecting with Jeyes fluid (or similar) to keep the algae at bay- now i have a larger north facing front patch:) to manage.- The west and east paths remained clear so it may well be just a North facing issue
    Jeyes fluid, scrubbing brush, elbow grease and maybe coupled the assistance of a power washer or strong hose on a dry day sounds like the solution....the last 2 wet summers have really compounded the issue and I have seen additional growths as a result,..so what you are describing doesn't sound unusual in itself, but depending on where you lived previously, you may not have experienced it or it may have been localised in an area you never noticed.Hope this helps-


  • Registered Users Posts: 1,013 ✭✭✭Curious Geroge


    Thanks for all the feedback guys but elbow grease and a wire brush are not an option. I'm not talking about gable ends facing north or simple patches of algae but the entire walls space of a 2 storey house (>30 yrs so not a new build) and all surrounding walls from top to bottom, garages and now the roof. I'm sure the power washing will clear the algae as it did last yr when I washed it off. I'm looking for a method of prevention and hoped that someone may have experienced and resolved a similar issue.. Thanks for all the feedback so far though.


  • Closed Accounts Posts: 14,144 ✭✭✭✭Cicero


    Sorry.. OP... on re-reading thread...sounds like problem is recent "2 storey house (>30 yrs)" so obviously localised to your own house and not a common problem in the area caused by general environment? (sea/humidity/wet summers etc etc) If this link is any use,...otherwise, over to the experts..best of luck

    Sorry for all the edits.. final one..you say you are co Galway based...from travelling to Galway for the last 30+ years (especially costal parts) I noticed mass discoloration of certain houses each year throughout all that time- the article below cites the environmental conditions where algae thrive.. it could be based on what the atlantic is throwing at you but after that, like I said, its over to the experts


    http://www.broward.org/air/roofalgae.pdf


  • Registered Users Posts: 103 ✭✭lapsed


    Powerwashing will only distribute the spores all over the place. Worst method ever.


  • Moderators, Home & Garden Moderators Posts: 10,135 Mod ✭✭✭✭BryanF


    Please check date on thread before posting thanks


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