Should I be worried about this plaster crack?

[jkn]

Hi all I'm been looking at the plasterwork of our 'master bedroom' with a view to redecoration in the near future. I am a bit concerned about a long crack in the plaster and given my naivety about matters structural am seeking advice as to whether I should be!

The crack is narrow but long; I am a little concerned about it for a few reasons:

- it runs from around the lintel area above the window (seems to be from where an old hole was drilled) - it runs across two walls, at a 'cross' angle which I think I once read was a warning sign of possible problems underneath - I can half-convince myself that on the 'upper' side of the crack, and in the corner of the room, the wall is a touch cooler/damper than elsewhere.

I have looked at the outside of the house but can't see any corresponding cracks. It's difficult to see near the window, as we have a 'hipped' roof (probably not the technically correct term, I think).

I guess I am looking for advice as to whether this is something not to worry about (ie. just fix the crack), whether I should get someone in to take a look at it, or ... some other action.

There are some photos here:

On a couple of the pictures I have 'drawn' on the crack, as it is otherwise difficult to see. I've indicated the 'cooler/damper' area on the image 'corner_from_inside_marked2.jpg', for comparison.

Any advice/thoughts welcome. We are on the South Coast, a 50s(?) ex-council house, built on a hill over chalk.

Thanks Jon N

[John Williamson]

If it starts glowing, call The Doctor. He'll bring Amy Pond and they'll sort it all out.

[Capitol]

Looks like there is some slight movement but nothing too significant. Has someone inserted a lintel at a lower level for an extension? How long has the crack been there? Brickwork is very tolerant so it doesn't look serious to me. It might benefit from a small plaster removal and replacement if you wish to redecorate as tiny cracks are often hard to fill cleanly.

[Tim Watts]

You may not if you have cavity walls.

It looks very superficial and whilst it might be following a minor crack in the inner brick leaf, it might just be a plaster crack with is very common.

Only a bit of it is horizontal (ie may be following a mortar join). The ends are at very funny angles and it is extremely rare for bricks to crack like that.

Personally I'd rake it out 2-3mm wide, PVA the edges, shove some polyfilla in and leave it.

If it gets bigger suddenly (and recracks your repair), that might be worth some investigation - but it probably won't.

[RJH]

Some very slight settlement? Looks to be only affecting the inner leaf, so I'd guess something happened around that part of the window opening. I'm not too sure how the crack's carried around the corner, though.

I'd just fill and monitor.

[harryagain]

+1. Another slight possibility is cavity wall tie failure especially given the age of the house and it's exposure to salty air. Uusally cracks also appear elsewhere located where the ties are.

Sometimes salty air can affect (ie cause corrosion) the steel lintel over windows in houses of the period.

But repair and wait and see is the best thing for the moment. Get a ladder and check out/repair the outside pointing too. The outside crack (if any) might be in a different place to the inner one they are separate parallel walls.

[The Medway Handyman]

As others have said, fill it & see.

Ex council, built in the 50's - it will have been much better built than any modern house.

[Chris Hogg]

ISTR from one of those TV home makeover progs (Ms Beeny?) that you only needed to worry about a crack if you could put your fingers into it. OTOH it was just a TV makeover prog.....

[Weatherlawyer]

It looks like the plaster has cracked along the joins in the plasterboard. How high off the floor are they?

It wouldn't go around the wall like that if there was a failure in the structure and it would be wider, dirty from water ingress and visible on the outside.

Scratch the crack out with a grout remover or an old chisel and fill it with gap filler (caulk) then forget all about it.

[jkn]

Hi all thanks for the helpful replies. I am heartened by the general consensus that it's unlikely to indicate a larger problem, & will go ahead with scratching it out and making good.

Pond and they'll sort it all out.

heh, nice one John --- and the idea has its attractions...

I don't think there *is* any plasterboard, it's plastered onto the walls. what makes you think there is? THe height of the window/lintel is ... about what you'd expect, 5'10" or so?

Cheers jon N

[JimK]

- show quoted text - It looks like the plaster has cracked along the joins in the plasterboard. How high off the floor are they?

It wouldn't go around the wall like that if there was a failure in the structure and it would be wider, dirty from water ingress and visible on the outside.

Scratch the crack out with a grout remover or an old chisel and fill it with gap filler (caulk) then forget all about it. /q

Caulk not suited here as it shrinks leading to an obvious repair. Poyfilla/equiv or one of the lightweight "Non shrink" ready mixed fillers is far better IMHO.

Jim K

[Stephen]

The house was stated to be a 1950's house.... Were they using plasterboard back then? I would have thought it would be a two coat plastering system?

[ARW]

I emailed the links to my Dad (a retired chartered survyor who worked in the subsidence department for Britsh coal). As there are no visible cracks outside it could possibly be the roof that has moved. How long did it take the craxk to appear and is it now stable?

[jkn]

Hi Adam

Thanks, I appreciate your efforts.

From what I have heard, the crack appeared sometime in the last 5 to 10 years. I have not seen evidence of it moving, but I have only paid attention to it in the last year or so.

Not quite sure how the roof moving would account for this; I'd be interested in learning more (even if it doesn't apply in this case).

I s'pose I should 'fess and say that I have boarded up the loft (OSB on top of Celotex) in the last 5 to 10 years...

Cheers J^n

[Weatherlawyer]

The house has got plastic double glazing, were they installing that in the 1950's?

The ceiling has gone in the same way but followed the joists. The angle of attack in the wall seems to follow a level. There is no other explanation to that as far as I know. But why would you take my word as gospel?

There are some idiots on here that seem to think that one can surmise any stupid idea they come up with from a post like mine. Some of them might be stark raving lunatics. How would I know? Let's hope you are not one of them.

[Tim Watts]

That won't be it.

A bit of OSB plus stuff is tiny compared to the weight of the roof structure.

[Tricky Dicky]

The roof could be responsible as the rafters are usually fixed to a wall pl ate on top of the inner leaf. General settlement or strong wind could have induced some slight movement. It does not look bad and if it's not getting any wider then probably not much to worry about. However, if you are concer ned use some of these

mm-pack-of-5/85398

Chase out the plaster so the strap can later be concealed, hooking the bent bit over the wall plate in the loft, a few screws to secure it to the wall plate and the wall and that should prevent any more movement. I am not sur e how many you will need but on some new builds I have seen them put them e very couple of metres.

Richard

[Tim Watts]

...

I suspect because newbuilds use those godawful celcon blocks and:

1) Cement doesn't have any adhesion to them compared to brick, so the top course is as wobbly as s**te (seen that many times on new walls I've seen being built); 2) Too light so very unstable.

[Roger Mills]

It's quite common for the wallplates[1] supporting the roof timbers - and hence some or all[2] of the weight of the roof to be mounted on the inner skin of the cavity wall. Any movement of the roof would then affect the inner skin more than the outer one.

[1] typically lengths of 4 x 2 timber, laid on top of the brick/blockwork and held in place by metal straps [2] If roof trusses are used, virtually the entire roof weight is supported by the wall plates. If the rafters are supported by horizontal purlins - set into the gable ends - the purlins take most of the weight, and the wallplates relatively little

[Roger Mills]

No. It will have had wooden window frames - which provided far more support to the surrounding brickwork than the replacement plastic ones do.

It's quite common to see some settlement when wooden frames are removed

- even when there's a decent lintel in place. You *have* got lintels over the windows, haven't you?!