Covering up cracks in internal walls

[JIT]

Hi all,

A friend of mine has a single-fronted, semi-detached, Victorian-era period home (c1900), in the inner northern suburbs of Melbourne.

Due to a number of factors (reactive soil in the area, large trees on neighbouring properties etc...) there are cracks through several of the internal walls (and external walls too), up to 1cm wide in some areas.

A recent Archicentre building inspection has noted these cracks to be quite significant, but common amongst properties in the area and of this age. Essentially, the house is not expected to fall down, but fixing the cracks permanently is very unlikely. Restumping, underpinning etc...may still not prevent further cracking.

My friend has done some basic things like removing a large tree in the rear yard close to the rear and side wall, and improving subfloor ventilation, as simple ways of helping to reduce the problem of cracking. They are considering a new damp-proof course, but this appears quite expensive, and as it is an investment property, she is not keen to do this at present.

The property is rented out at present.

The question here is -

What can be done to cover up the cracks, cosmetically?

ie, given that permanently fixing the cracks is unlikely, what can be done to improve the cosmetic appearance of the walls?

1. The simplest thing, I presume, is filling the cracks with plaster and repainting...but with a change in climate and further movement, they will obviously just re-open.

2. Another option, using a fibreglass or paper plaster tape to cover the cracks, then repainting. I am not sure how lasting this method would be? Will it last longer?

3. Another option, using plywood or pine-panelling as the internal wall cladding, would these materials be less likely to crack?

I am looking for the simplest and most lasting solution to this problem of cracks. Mainly a superficial, cosmetic solution, so that when my friends property is re-valued by the bank, or is for sale, or open for new tenants, it looks good on the outside...

Any thoughts or ideas would be much appreciated...

GSJ

[rod@plasterbrok]

We have a section in our web site on repairing lathen plaster.

The repairs if done properly will last provided no further movement occurs.

You have no control over that. Over time there will be new cracking but that is the same for most buildings.

No one put more effort than me into crack prevention in my new home. But 5 years in and some minor cracking has occured in stress areas. I will wait another year or 2, then repair them.

Any superficial repairs will definitly crack again, the crack has to be dug out and filled properly.

The plywood is not a very good option it will look like ****T

Lining boards will work if you like the timber look but expensive and way too much timber, and would not suit the era.

Another option wich is also expensive but the best option for long term, is to rip out all the lathen plaster and replace with plasterboard. This is a major renovation though!


Cheers Rod Dyson

[JIT]

Thanks Rod,

Is it not possible to just put a new plasterboard on top of the existing wall, hence covering the cracks, instead of removing the lathen plaster first?

Also, the plywood, can´t you paint the plywood?

GSJ

[Tools]

I agree with rod.Ply will look like painted ply,not like plaster.Is it a timber house or brick?

Tools

[rod@plasterbrok]

You can put plasterboard over the lathen plaster. In fact its a good idea where you can, as it will add to the insulating and soud proofing qualities of the home.

However if you are going to do this you should remove and replace all skirting architaraves and cornice. Here you are getting into major renovation work.

We have in the past, (at the owners insistance) put plasterboad straight over the lathern plaster WITHOUT removing arc's skirtings,etc. The problem is how to finish off where the plasterboard butts against dissimilar surfaces. Casing bead looks terrible, stopping up will crack, and stopping angle makes the job expensive and will also hairline crack eventually.

Not to mention you will lose all definition in the edges of skirting, cornices, etc. I really is not a good look.

As metioned above, ply will look like ply. YUCK!!!!

If you can't afford to strip out and replace the plasterboard profesionaly, then don't do it at all. It won't help the value of the place if its not done right!

Do the next best thing. Patch the cracks properly as shown on our web site. We also show what is "patchable" and what is not and how to do it.

Cheers.

[JIT]

Thanks,

What a great forum...just like somersoft.com.

It is a brick house.

Rod, it sounds like the best option is the plasterboard sheeting, and if doing it properly and removing architraves etc...then it will be costly...do you know very rough ball park figure for say a 2 bed house with floor area 100m2??? I have no idea what sort of numbers we are talking here?!

Of note, the hallway is the only area of the house where there is virtually no cracking, and I believe there may be plasterboard sheeting here from the architect´s comments.

Otherwise, filling cracks properly would be my other option...

Is "flexible sealant" something that could be used here, since there has been and may continue to be some movement in the house???

Regards,

GSJ

[rod@plasterbrok]

No! Flexible sealant will fix the cracks, yes, but you won't be able to "hide" the cracks with flexible sealant.

It can't be sanded, and it shrinks, etc.

I have no idea what the cost of replacing the architraves etc. would be. The cost of plastering would depend on the type of cornice etc.

It is the sort of job you would need to carefully cost out before starting, so there are no hidden surprises. You would need to factor in electical costs etc. as well.

Where in Melbourne is the house? I may be able to call in over the next week or so and give you an idea which is the better option. We only contract out on new housing and units etc. So I would NOT be able to do the work. But I would be happy to give you an estimate of what you would expect to pay a reasonable contractor for the plastering only.

Cheers

Rod

[JIT]

Thanks Rod,

The house is in Northcote.

I am overseas at present. Will try and contact you on my return.

Will do more investigations re. costing in the meantime.

This thread has been very helpful for me.

GSJ

[rod@plasterbrok]

GSJ Northcote is good email me when you get back.

HJO, render works well. The only probelm with it is that, most people find it hard to work with. and even harder to get a quality finish.

Digging the crack right out back to the substrate is the most important thing with fixing cracks. When you have done that what you fill it with is not that important. Some products give a better result than others astheticly and are easier to use for various reasons.

Cheers

Rod

[journeyman Mick]

If you get a quote to cover the walls with plasterboard then you'll also need to get a quote form a carpenter to remove all the skirting and architraves and to refit them. The problem you'll encounter though, is that the walls will be 2 x 10mm thicker, thus the jambs will be 20mm too narrow and the hingepoint of the doors will be back behind the plasterboard. The doors will need to be removed and rehung on the extended jamb and the hinge and lock mortices will need to be patched and recut. More work, more money....

Mick

[Tools]

If you are going to take the render option (which is the cheapest and in keeping with the house),make sure you fix some expanded metal over the cracks and fix them to the brickwork on each side.Even a heavy chicken wire will do.Then render and set over the top.

Tools

[Cobber]

Ive got some issues similar to you with plaster which is lathen in a couple of rooms in my house. I'll take some photos soon and post them. I took away the wallpaper an in the corners of the rooms there is like a strip running from the roof to the skirting board joinging the plaster (i think). I have no idea what it is but it looks crap!

I just got my house restumped and the cracking is not as bad as expected which is good. I'm hoping to not have to replaster because of the cost (the extension is costing enough!) so Im hoping tp patch it up uf I can figure out what to do with the corner strips.

Good luck with your efforts repairing the plaster and let us know how you go.

[myla]

hello,

if cracks <2mm i would you use a good quality sealant like Sikaflex (around $17 at bunnies)

even up to 20mm (2cm) this stuff can be used it is a very high quality polyurethane sealant

keep flush with wall, any excess can be sanded, but you dont want to sand your finished sealant, ie, sand of any excess on sides of crack

when painting over it needs to be done in two distinct coats with 12hrs drying time between coats

is best overcoated with textured paints or suede effects paint, something with a bit of hiding power and flex.

I believe this would be the most cost effective way

have rectified numerous render jobs this way

the sikaflex will allow for movement to occur and most arylic paints have a little bit of give to them

apart from that, I would think rendering would be the next best thing

if substrate is reasonably sound, but cracks would still need sealant and mesh appiled in wet render over the top or expanded metal as mentioned

thankyou
myla

[Cobber]

Looking at this photo from an old posting maybe I dont have lathen plaster?

http://www.woodworkforums.ubeaut.com...7&d=1098868722

Part of the plaster has detached itself from the skirting board at the bottom. When I push the electrical plug in the powerpoint I can push the plaster in. Judging by this photo it wouldnt be possible?

How can I tell easily whether its lathen or not???

[rod@plasterbrok]

is best overcoated with textured paints or suede effects paint, something with a bit of hiding power and flex.

That is because you can't get a high quality finish with sealants.

The line of the crack will always show up unless texture finished over.

Everything you do will work to some degree or another.

What you end up with will definitly be determined by your skill level or how much you are prepared to pay.

Cobber you have got lathen plaster there.

Cheers

Rod