Correct material for crack repairs

tcs

I posted well over a year ago about cracks in my front bedroom wall but as the house wasn't about ready to fall down it didn't get attended to then and there. FYI, post is http://www.boards.ie/vbulletin/showthread.php?t=320009

FWIW, that crack hasn't let moisture in since though I have checked it after every heavy bout of rain.

I'm now trying to get my kitchen done and in the very heavy rain over the last week or so, I noticed damp spots on my kitchen wall. One caused by a vent being moved in the past (quite badly!) and another below it caused by a horizontal crack in the wall that appears to have been filled/sealed(?) before - I can see this from the outside.

Anyway, I'd someone in to quote me on the kitchen - electrics/plumbing/skimming/putting in new cabinets etc. - and he lives in the locality (i.e. in an identical house). He talked about widening the cracks and then filling them with silicone. Is that the correct 'filler' to use?

Someone mentioned epoxy resin to me some time ago as the appropriate thing to use. If you look at say http://www.ramservices.co.uk/html/leak_sealing.html you'll see them talking about

a variety and combination of caulking compounds and injected cementitious, epoxy, polyurethane and acrylic resin grouts.

This sort of looks like the sort of crowd you'd go for if you'd a leak in the Port Tunnel!!

http://www.basementanswers.com/leaking_basement_crack_repair/pages/content/article_drain_tile.html talks about repairs to basement walls -

Crack injection (with either injection epoxies, polyurethane foams, or polyurethane grouts) is the best and most economical method for repair of a leaking crack on the wall of a poured foundation... The use of polyurethane foams or grouts have joined injection epoxies as products of choice in repairing leaking poured wall foundations.

I don't have a flooding basement like http://concretenetwork.com/concrete/crack_injection/ or anything.

Another site - http://www.dwyercompanies.com/residential/slabcracks/default.aspx

Not finding much like this on Irish websites - there's one crowd in Wexford (http://www.renobuildireland.com/crackinjection.html).

Is all this stuff I'm reading on the web overkill? Is yer man down the road's approach of using silicon a sound one?? Is silicon a completely different beast to any of these mentioned products? Can it compare? Do I need the super-duper solution?

GreeBo

I guess it depends on what the material i and why is it cracking?
Is it subsidence or is it just a cracked render?
How old is the house?
If its just a render crack then you should be ok filling it with silicone to stop water getting in..if its more serious then you probably need to look deeper into it. (pardon the pun!)
Can you tell if the crack is on the render or the brickwork?

tcs

It's not a brick wall - it's poured concrete (60+ year old ex-council house). Apparently such cracks are fairly typical as something's gotta give.

mad m

Well if it was me I wouldnt like to just put silicone into it. I had a crack under my sill out front of house,the crack actually went through house to sitting room(hair line) 1940's house,got an engineer to look at it and suggested to open it out and while I was doing work on crack dig down and look at foundations to make sure house didnt need under-pinning. So thank god it was a type of crack that was fatigue over the years,its common in old houses.Its normally noticable around reveals or cracks going from sills above going down to reveals below.

Well engineer told me that if house didnt need to be underpinned then it was a matter of opening crack atleast two inches on both sides as this was the case for me. Get a solution called (damn cant remember name)ronaldfix I think and put it into cement while mixing,it makes cement really sticky,but first remember to polybond crack a couple of times before putting any cement in it.Now get some expanding metal and cut wider than crack and nail home,use some bonding over it and then skim.

Well thats what I did front and inside of house and crack(thank god) hasnt come back.Got the front white dashed to hide expanding metal.