Hairline Cracks Help Please

[lyndasfarne]

We have hairline cracks appearing in the external walls of the house, in the front room. We are not sure if it is down to the poor plastering of the guy who lived here before or common movement of it being a Victorian property. We have rubbed down, applied fine crack filler over them and rubbed down again, but they still keep coming back.

I have heard that they should be cut into first then filled, I am a little worried about doing this in case I make them worse. I wondered if having the walls replastered or skimmed would cover them up for good or would they still appear later??

Would be really grateful for advice.

Many thanks

 

[Lime]

If a crack continues to move, no amount of filling will hide it.
however if it is an old crack or a new crack on new work you will have to rake out the crack to fill it properly.
The width of a small screwdriver blade will do.
Wet the crack before filling it and use something like pollyfilla.

 

[Feltwell]

Rake the crack out so it is an inverted "V" - so angle whatever tool you are using to scrape it out with, so that the base of the crack within your wall is wider than the visible front bit. Then make sure you push the filler home well when you do fill the crack. If you just fill "over" the crack it will reappear. Don't be afraid to rake it out properly, you need to get back to good sound material that the filler can bond to properly. A smear of new filler over the top of a narrow crack that may have loose material in it will fail. As Lime says, wet the crack before filling.

If the crack keeps re-appearing after that then you need to investigate further what is causing the movement. Skimming over a crack caused by movement won't work. Don't panic though, first thing to do is fill it properly and then see what happens.

 

[middi]

If the house is Victorian and it is still standing, there cannot be much wrong with it.
I think you should only worry if the cracks appear on the external faces of the wall that can be seen when standing in the garden.

Just cut " V " grooves, as already advised, in the existing cracks and refill.

Also, if you have a "bouncy" floor with the floor joists running parallel with the wall where the cracks are you will be facing a loosing battle unless you stabilise the end floor joists.

Middi

 

[Feltwell]

If the house is Victorian and it is still standing, there cannot be much wrong with it.

That's kind of my thinking as well Middi. Broken drains or the effect of trees is still a possible, but with hairline internal cracks only then chances are there is no problem. Good point about the joists.

 

[middi]

Absolutely right about drains, trees etc.., if there are no visible cracks in the exterior of the house ( and things being equal), I wouldn't have thought there was a major problem.
Nevertheless,as you say, one can never tell what is going on with these old properties.

Middi

 

[lyndasfarne]

Thanks for all your replies.

Rather thought it would be having to deepen the crack and fill it!! So not really surprised there as we have failed with other methods.

There are no cracks on the outside walls thankfully, and no trees or drains near the offending wall on the outside. Maybe the floor so will investigate that.

Will follow instructions and fingers crossed that it will work this time!!!

Many thanks again.