Cracks in external render/how to fix

reggaeman

I have a few long cracks on the outside render. Would anyone know what I should use to fill in the cracks. I want to get it done before the bad weather sets in. One of the cracks has algae in it. Thanks.:(

sullzz

I think firstly you need to find out why the cracks started , and are the cracks passing through to the inside

paddy147

depending on the render mix and how it was applied,and also the length of the wall,you may need to have an "expansion strip" installed on the wall.

Some plasterers put washing up liquid into the render to make it fluffy and make it easier to apply.

This sometimes can cause the externak to give way and crack.

plasteritup

reggaeman wrote: »

I have a few long cracks on the outside render. Would anyone know what I should use to fill in the cracks. I want to get it done before the bad weather sets in. One of the cracks has algae in it. Thanks.:(

can you post some pics reggae?

reggaeman

Thanks plasteritup. I will do that. The cracks are like hairline cracks. I filled in some with a siiacone last year and they havent got any worse. But a few more have started to show.And im afraid the algee getting into them might make it worse.

paddy147

reggaeman wrote: »

Thanks plasteritup. I will do that. The cracks are like hairline cracks. I filled in some with a siiacone last year and they havent got any worse. But a few more have started to show.And im afraid the algee getting into them might make it worse.

Sounds like shoddy external rendering work,if small hairline cracks are appearing.

I had this same thing on a long garden wall before.

GI gt in a "city and guilds" plaster,er who took off the cracked render and he then added in an expansion strip (should have been installed originally,but wasnt) and re-rendered the wall.

Never had a single problem since.:)

reggaeman

This is the link for photos

http://www.flickr.com/photos/capturepics/

plasteritup

reggaeman wrote: »

This is the link for photos

http://www.flickr.com/photos/capturepics/

reggaeman it looks like bad settlement cracking,id imagine the final coat of render was maybe far to strong a mix also ie to much cement,there really is not much you can do other than score back into the render and repacth the areas cracked,but if cracks are still appearing that may be a never ending process.

reggaeman

thanks plasteritup. can you suggest what i should use to fill it in.

cnocbui

Bostick Wet-Grab (B&Q) or Tec7 (white)

Much better than silicone in my experience. Flexible, so hopefully will cope with any further movement if it is minor.

I have used Wet-Grab on a large settlement crack in my house and so far so good.

paddy147

Do the job propperly,get it re-scudded and a propper external top coat applied.If needed,also add an expansion strip too (depending on wall length).

Do it propperly and you will never have any more problems.

Job done.

plasteritup

paddy147 wrote: »

Do the job propperly,get it re-scudded and a propper external top coat applied.If needed,also add an expansion strip too (depending on wall length).

Do it propperly and you will never have any more problems.

Job done.

i tend to agree,one or two of those cracks look like an area around the cracking could possibly be hollow,check this with a light tap of a hammer,if it is chip away what is hollow and cut a nice edge either side of crack and re render,that is what i would do.

paddy147

cnocbui wrote: »

Bostick Wet-Grab (B&Q) or Tec7 (white)

Much better than silicone in my experience. Flexible, so hopefully will cope with any further movement if it is minor.

I have used Wet-Grab on a large settlement crack in my house and so far so good.

You have only masked the problem then.

Did you scrap it out or angle grind out a small section of it and check for any signs of cracking and or subsidence in the actual blockwork/building/wall????

reggaeman

Hello Plasteritup. Just managed to get back to my PC. I checked the wall for hollow bits but everything is OK. Dont fancy using a angl grinder on it. I think your right about a bad cement mix. I had a look around the rest of the estate and it seems most of the houses have the same problem’ it only occurs on the side of the house as the front and back are ok. These are semi’s. I put the silicon on some of the cracks just to stop water getting in but when I paint over them the paint won’t take to it. I have to find something better to fill in the cracks. I might try that Bostick CNOCBUI wrote about.
Having asked around on the estate it seems it was a bad builder who did the work.

paddy147

reggaeman wrote: »

Having asked around on the estate it seems it was a bad builder who did the work.

...who probably made a nice healthy proffit too,for shoddy workmanship.:rolleyes:

Sorry to hear this,but IMO,the only and propper way to address this probem is rerender the side of the houe propperly.

It might cost you a bit in the short term,but in the long term it will be piece of mind and job done for good.

Regards.

reggaeman

Thanks Paddy147.