Covering up cracks in internal walls

GSJ · Aug 05, 2006 5:24 am

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

micky · Aug 05, 2006 12:55 pm

hey gsj........................i will try and be as helpful as i can, this is not a big problem in suburbs north of perth as its mostly good draining sand

a good way to stabilise the soil may be use a sub soil drain on the high side of the house if it is on even a remotely sloping site..................basically a trench dug put in agricultural drain and cover with blue metal then good san then top soil, have sub soil drain so it diverts water away from the high side of your friends house and helps to keep the moisture content under the house stable.

also note if and garden beds and as you have said trees are impacting, ie a garden bed up near a house when water will heave applying pressure to the footings. ideally your friend would have a footpath all the way around that allows water to run away from the dwelling.

once soil is stabilised you can fill cracks with plaster and paint. depending on who is patching the crack fibreglass tape is easier than paper tape but paper tape is stronger. the other thin to consider if you tape joints is the light because taping will slightly raise the wall surface so you really want to plaster out quite wide and feather out edges before sanding.

hope this is of some

good luck

builda · Aug 06, 2006 12:29 am

What suburb in Melbournes north? There are extensive areas of highly reactive basaltic clays that create havoc with buildings - especially the older ones.

Quote:

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?

No, I believe too superficial as the problem is not with the plaster but with the ground that the building is founded upon

Quote:

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

Sight unseen, I would clad in plasterboard sheeting as it is slightly more flexible than the solid plaster that is most likely currently in-situ.

Is the building solid brick, I have made that assumption. If so, plasterboard needs to be 'stick on' but this is a big job as all the door and window architraves are affected as well as the skirtings.

If possible, can you post the archicentre report as they have seen the building?

micky · Aug 06, 2006 12:41 am

g'day builda just read your post and what your saying is to possibly dryline the troubled room..........................as you are probably more experienced with reactive soils would you also try to make site more stable or is drywalling a pretty good fix

cheers

builda · Aug 06, 2006 12:53 am

In reality those reactive clays can go very deep and it becomes just too big a job and as was already posted, no guarantees. Underpinning can actually create worse problems on these sites so it is an option not to be undertaken lightly and without very detailed engineering.

Perhaps if they did one room first, left it for 12 months (the full season) and if it worked then do a room by room over time to maybe save cost.

I've also seen 20mm cracks in plasterboard walls so if there is enormous movement then obviously this is not a solution but if the cracks are small (less than 2mm) then sheeting may just work.

GSJ, you do need a bit more work on this at a professional level before you waste thousands of dollars on a solution that will not work. If you can post the archicentre report then we can have a quick look for you - gratis!

GSJ · Aug 06, 2006 1:44 am

Hi,

Thanks for the replies so far.

Builda...it is brick house in Northcote.

There are neighbours who have underpinned and this has not been successful at all. So this is not an option I think.

Cracks at some places up to 10mm.

Of note, the hallway of the house is the only place where there are virtually no cracks...and I believe it may be covered with a plasterboard sheeting...so perhaps using this on the rest of the house may have a good or better outcome...?

If it is a big job due to the effect on architraves etc...then may have to just leave them, and do a fill up job when the property is for sale or for rent or being re-valued for the bank...

Builda, would you have a very rough ballpark figure of how much it could cost for a 2 bed house with floor area 100m2???

Unfortunately I am overseas at present so I don´t have the building report with me. Will try and get it soon.

Any experience with a "flexible sealant"...could this be of use here to fill up the cracks, given there is some movement in the house...?

Certainly would get formal professional advice before proceeding with anything...

GSJ

Chester · Oct 13, 2006 5:59 pm

If the soil has shrunken causing settlement of footings, resulting in internal cracking, URETEK deep injection can resupport and lift the footing back to a suitable level. Better option than cannabalistic underpinning.

3timesbuilda · Oct 16, 2006 10:13 am

Maybe you could use bathroom sealant, It may stretch and move more freely. You could then also consider wallpapering over it. Prorbaly not last forever but will probably buy a bit of time.

beglobal · Oct 17, 2006 8:33 am

micky

hey gsj........................i will try and be as helpful as i can, this is not a big problem in suburbs north of perth as its mostly good draining sand

a good way to stabilise the soil may be use a sub soil drain on the high side of the house if it is on even a remotely sloping site..................basically a trench dug put in agricultural drain and cover with blue metal then good san then top soil, have sub soil drain so it diverts water away from the high side of your friends house and helps to keep the moisture content under the house stable.

also note if and garden beds and as you have said trees are impacting, ie a garden bed up near a house when water will heave applying pressure to the footings. ideally your friend would have a footpath all the way around that allows water to run away from the dwelling.

once soil is stabilised you can fill cracks with plaster and paint. depending on who is patching the crack fibreglass tape is easier than paper tape but paper tape is stronger. the other thin to consider if you tape joints is the light because taping will slightly raise the wall surface so you really want to plaster out quite wide and feather out edges before sanding.

hope this is of some

good luck

Interesting idea... hope it works!!!

Plaster Brokers · Oct 19, 2006 12:17 am

Hmm this topic was done to death at the wood working forum CSJ there is no magic fix here.

Trying to do this job on the cheap will only result in failure. NO FLEXIBLE SEALANT IS GOING TO DO THE JOB FOR YOU.

Either repair the cracks properly or re line the walls with plasterboard, or just leave the cracks. These are your only real options.

But only after you have sorted out the overall stability problem.

Rod.