by DocMartin »
Mon Nov 19, 2018 11:47 pm
I have a 1930s house built on clay soil and it has worse cracks than that. The worst was about 6mm wide in places.
Outside cracks tend to end up at the corner of a window somewhere as windows concentrate the stress.
Inside I get similar small ceiling cracks. They are either along the interface of the wall and ceiling or at 45 degrees. Cracks at 45 degrees are shear cracks. They indicate things trying to slide past each other.
My own personal opinion is that unless these cracks have suddenly appeared, it's no big deal and you just keep up with them.
Given these cracks are in Artexed ceilings I guess this is the extent of the cracking since , what, 1980-1990? Not very fast at all then.
In the case of my house, I think the cracking has been caused largely bythe north wall being solid brick and having only a few tiny windows in it, compared to the large bays, studding and doors in the other walls.
This causes differential settlement, with the north wall sinking into the clay soil at least an inch over the past 80 years. This doesn't leave a jagged one-inch step in the brickwork somewhere though - the house just kind of deforms and cracks a bit. The roof I think has been left behind a bit - it is still sitting on the walls just fine but I can see a gap in the soffit boards and the movement shows up in the house at the ceiling/wall interface especially upstairs.
I also have slanted doorframes - my front door, back door and toilet door are both close to the north wall so show the distortion the most - the side of the frame attached/close to the north wall has gone down with it but the other frame further away hasn't so much. I have had to trim the door a tad at top and bottom as a result.
As for the bigger cracks - I knocked the pebble dash off and repointed in one case, replaced cracked bricks in the other, then repebble-dashed. I wouldn't recommend knocking off the pebbledash as it requires quite a bit of skill to match it. So, if it were me, I'd fill the interior cracks with something - maybe something flexible - certainly along the wall/ceiling interfaces. I believe you can get flexible fillers. It prevents the filler from cracking again too soon.
Also, I'd try and figure out where your cracks are coming from. It is no doubt due to the clay soil one way or another, but it would be as well to rule a few things out. Have you got a water leak? I had long-term leaks under my outside soil-pipe and gully, but I don't think they were the cause. Do you have differential settlement as I described? Have you got a thirsty tree (like a Willow) close to the house?
As for the outside cracks, You could try and use an exterior grout perhaps. Get something with a sympathetic colour to the pebbledash if possible. Try a small section of crack first to avoid messing your pebbledash up if it goes every (sponge and bucket of water handy?).
Regarding the insurance company. Up to you. I don't imagine they'd underpin your house for the cracks you've shown, if they've taken years to develop. If anyone else knows better though, then fine, take their advice. I'm only guessing about the insurances likely reaction.
