Jackie Posted May 20, 2007 Share Posted May 20, 2007 The south side of our house, covered in exterior crepi, is somewhat stained with streaks of grey/black mould. The crepi appears to have lost a lot of its yellow colour though this may just be a coating of mould/dust. As an experiment I have power washed an area with goodish results to the extent that most of the mould has been knocked off though not all as there is still some slight staining. Sand grain size particles of crepi have also been removed and the yellow colour has only been slightly restored.I tried another area by spraying with extrait de javel (9.6% active chlore) but no power wash, with even better results and no loss of the crepi surface. The colour of the crepi in the second case seems to have been modified back to a deeper yellow which seems strange given the bleach characteristics of javel. My question is which, in your experience, is the better method as I want to clean the whole front of the house without damage to the crepi. To play safe I hosed off the test area that had the javel applied after about half an hour just in case the chemical had some bad effect on the structure of the crepi……………John Link to comment Share on other sites More sharing options...
Jonzjob Posted May 20, 2007 Share Posted May 20, 2007 We have the same problem on the West side of our house. I tried a small part of one of our West facing walls and sprayed it with a fairly weak solution of javel. It cleaned up lovely, but it is not very enviornmentally friendly at all. If it gets near any plants it will kill them. I have also been told that it effects the crepi in a detrimental way. I have also pressure washed most of the West face of our house almost a year ago. It didn't clean as well as the javel, I got covered in the sand type particles you spoke of and we now have the mould growing back again. I also nealry froze to death!! even though the day was fairly warm.You can get eco friendly(?) anit-mousse products, but we have yet to find one that works. We even had a couple of blokes round offering to clean the crepi and they gave us a demo of what it would be like. They sprayed a small part of our garden wall a few weeks back, stood back, waited and it's just as well they didn't hold their breath too, because it still hasn't changed at all [:-))]... I hope they aren't holding their breath waiting for a phone call?If you do find a product we would be VERY interested to know what it is, but I would be reluctant to use javel, especially at the strength that you mentioned. Household bleach is about 2 to 3% active chlor... If you do use the javel then please be very carefull about where the spray goes. In your eyes and you could have real trouble! Link to comment Share on other sites More sharing options...
suein56 Posted May 20, 2007 Share Posted May 20, 2007 [quote user="Jonzjob"]We have the same problem on the West side of our house. I tried a small part of one of our West facing walls and sprayed it with a fairly weak solution of javel. It cleaned up lovely, but it is not very enviornmentally friendly at all. If it gets near any plants it will kill them. [/quote]We want to do the same as you on our west facing wall but have no idea what concentration to use, we intend to use domestic javel ie approx 3%. What do you term 'a fairly weak solution'?Sue Link to comment Share on other sites More sharing options...
Jonzjob Posted May 20, 2007 Share Posted May 20, 2007 I had a small bucket of water, put a small amount of javel into the water and tried it till it started to kill the mould and change the colour of the wall to what it should be. It would be a guess, but probably not as much as 3%. The javel was probably about 9% to start and I definately didn't put enough in to dilute it to 1/3 of the start. But I must admit that I would not do the rest with it. we will keep looking for a good, friendly anti-mousse...When I found an effective solution, I sprayed it on the wall and washed it off with a hose within a couple of minutes. Lots of water....... Link to comment Share on other sites More sharing options...
WJT Posted May 20, 2007 Share Posted May 20, 2007 We need to do the same but ours is crepi with exposed stone and wouldn't want to kill the plants around the house nor do any harm to the wildlife. We have loads of lizards and I would think bleach would harm them. If not, I would like to know or please let us know the solution you come up with Jonzjob. Link to comment Share on other sites More sharing options...
suein56 Posted May 20, 2007 Share Posted May 20, 2007 [quote user="Jonzjob"] When I found an effective solution, I sprayed it on the wall and washed it off with a hose within a couple of minutes. Lots of water.......[/quote]Great - thanks. Our landlord said that he used this method between outgoing and incoming tenants ie approx every 3 years, but did not mention a solution strength. We only have a few small patches of 'champignons' at the moment so want to clean them off before they become too unsightly. We have a narrow band of gravel around the house so no danger of harming plant life, though I take the point about the lizards as we do seem to have an extended family of them who live somewhere underneath our tiled terrace.As an aside I am impressed about how good the crepi still looks as the house is nearly 12 years old. Sue Link to comment Share on other sites More sharing options...
Charlotte3 Posted May 20, 2007 Share Posted May 20, 2007 In work we have lots of public housing contracts for this work.We Karcher the walls using water and then apply industrial strength anti mousse. This will kill plants for the growing season, but they normally grown back next season. (NB. the machines we use are very powerful, not like the domestic variety, so I suppose the results will be better). We always look for environmentally friendly alternatives, but haven't found any yet that actually work.I would not personally ever use bleach on Crepi as it will break it down.Aly Link to comment Share on other sites More sharing options...
Beryl Posted May 20, 2007 Share Posted May 20, 2007 We used a spray that we found in the outiror catalogue (you can buy online direct but I can't remember what it is called [8-)]) it was guaranteed to clean off mould and stop it growing back for a few years. So far so good. Link to comment Share on other sites More sharing options...
Jonzjob Posted May 20, 2007 Share Posted May 20, 2007 Outiror are one of the companies that have those huge artic trucks that visit the place every now and then. I will keep an eye out for it next time... They do keep coming back, so they can't be that bad? Link to comment Share on other sites More sharing options...
Jackie Posted May 21, 2007 Author Share Posted May 21, 2007 Thanks for the replies folks and I have done the whole side of the house using the javel with really good results. I take note of the warning about using javel and may try to find an alternative to it and pressure washing as am not happy about the amount of little bits of crepi that come off.I will monitor the crepi to see if the javel has in any way produced long term damage but it looks ok at the moment. Some weeds at the bottom of the wall have snuffed it so I can confirm the danger to plant life. The strong smell of chlorine has almost all gone and no permanent damage to wildlife that I can see............John Link to comment Share on other sites More sharing options...
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