Covering up cracks in internal walls

[JIT]

Hi,

I recently contacted a company called ´Constructa´ in the UK that is experienced with Victorian era properties and their related structural/maintenance problems.

They recommended a unique way of structurally re-inforcing/fixing cracks to a building that has had cracking problems, that is able to deal with future movement issues and prevent further cracking, that is not like underpinning, restumping, or the Uretek injection mentioned earlier in this thread.

This is very interesting. The product used is made my a company called Helifix, and they have a presence in Australia too.

Following is a copy of the e-mail I received from Constructa, who were very detailed and quick in their response to my enquiry, thanks to Mark Genney from Constructa for this contribution to this informative thread (see the link to Helifix for more information on the product):

Hello GSJ and greetings from the motherland!

You quite rightly point out that the problem is not only covering up the cracks but ensuring that they do not return. You rightly suggest that covering or filling a crack in a property that is continually moving will actually not prevent the crack from reopening.

We use various technologies for the repair of Victorian properties, however in this instance, I would suggest the use of “crack stitching” prior to making good with a good quality filler. We exclusively use the products of Helifix for crack stitching, by chance Helifix has a good Australian presence and a website that seems identical to its UK equivalent.

If you go here http://www.helifix.com.au/crack_stitching.html you will see the application and use of their “Helibar” system with fairly descriptive diagrams etc.

In your case we would probably break out the plasterwork 1m either side of the cracking, chase out the mortar every third or fourth brick course, insert helibars into these chasings.

Re-point in the chased brickwork with a strongish sand cement mix (3:1 is ideal) then replaster the area.

Having read the forum that you have posted the question in, I wouldn’t recommend the short term cheap fix that you are looking for, you will be surprised how quickly badly fixed cracks in Victorian properties reopen, if it is worth doing, it is worth doing properly.

Hope this helps

Best wishes

Mark Genney

constructa:

freephone 0808 145 5544
email [email protected]
web www.constructa.co.uk


I will contact Helifix in Australia to get more information and approximate pricing and post the details on the forum.

Any thoughts/comments?

GSJ

[myla]

hello,

used to deal with a chap (John Geraghty) who was handling the Helifix in Vic many years ago

he also designed many brackets for Hebel construction

I wouldnt think the sikaflex is a short term solution, many people use this product for waterproofing showers, caulking external expansion joints, sealing external/internal cracks for many years now

it is surprisingly stable being a polyurethane

common practice by painters repainting homes is to seal "hairline" cracks which commonly occur at junction of ceiling and cornice or wall and skirting prior to painting

normally using "no more gaps" though

thankyou
myla

[JIT]

Myla,

John is still doing the Helifix work in Victoria I believe as I was given his name by Helifix Australia.

From my initial research of Helifix, it seems it is quite commonly used in the UK and is an accepted strategy used to stabilise structures. It obviously needs to be done after review by a specialist/geo-technical engineer.

GSJ

[JIT]

Hi,

This might be an obvious one, but what about covering up the cracks in the internal walls by using some type of wall paper/covering???

Is there some sort of flexible type wall covering material that could be used???

I guess this would be like the plasterboard sheeting option, where the plasterboard covers the cracks, and because it is a flexible material, it allows for further movement.

Any thoughts/comments?

GSJ

[JIT]

Hi,

I think I am the only one still interested in this thread/topic! - but, for the sake of completeness I thought I will post the results of my further research into this problem of cracking.

I started threads on several UK property investment forums (figuring that they have many more period properties in the UK, also have reactive clay soil areas and probably much more experience with cracking problems), the best were:

www.periodproperty.co.uk
www.oldhouseweb.com

I got some very good replies and suggestions.

Here are a couple of the good posts:

(1) ´I don't think there is any way you can prevent cracks reappearing if there is further substantial movement.
If there is a prolonged drought followed by heavy rain some movement is almost bound to occur.
The most flexible wallpaper will tear and ripple over a moving crack.

However, looking on the bright side, the cracks may not move substantially again.
Often cracks appear in the early days of a building's life and stop moving to any great extent after a while.
Most older houses built on clay have old cracks.

Many people make the mistake of just plastering over the cracks only to find that they usually reappear shortly after.
It should be remembered that once brickwork is cracked there will always be some slight movement caused by thermal fluctuation or vibration.
If the patch plaster is too thin it has no strength and cracks easily.

The most effective method for small cracks is to rake them out right down to the brickwork (or lathes) leaving a gap in the plaster of about 5-10mm.
Any really loose plaster should be removed too but don't pull it off as that will loosen more plaster. Use a light chisel, knife or sharp screwdriver and cut the plaster off.
Remove the dust and wash the crack out.
Then fill the gap completely using an appropriate filler (polyfilla is quite good in this situation as it has good adhesion with some flexibility with strength) and sand it down.
Then decorate in the normal way.
I have found this method normally lasts for some time and is able to resist minor movement.

If the cracks are greater than 5mm it is sensible to remove the plaster directly over the crack and attempt to insert some mortar between the bricks to stabilise the fault. It may be necessary to remove some original mortar to get the new mortar in place.´ (posted by Lime from the forum at periodproperty.co.uk)

(2) ´May not have your solution, but I can add a few ideas to your bucket. A few years ago I had some shifting problems in an out building with a poor foundation.I essentially used a combo of your suggestions #1 and #2.

I dug the cracks (about 30) substantially deeper (as deep as I could) and wider with a knife, then I filled them 3/4 of the way with a flexible sealant. I let that dry (rubberize) a few days and then used a standard spackle for the remaining 1/4. This allowed me to paint and the surface and the somewhat larger more flexible cracks were able to acccommdate some of the movement. This was not a 100% solution. I still get cracks. The building is still "active." But the cracks I filled generally stayed filled. Maybe 20% were incurable based on the shifting weight/stress points the building. But it helped. Might be worth a test. Really not as much work as it sounds. And it was about $10 of material.

I failed intially becase I didn't use enough flex sealant. The spackle should really just be a paintable topper.

I know they make silicone spackle which is presumably paintable but I have never been able to locate. Must be special formulation.´ (posted by d18mike from the forum at oldhouseweb.com)

From these replies and reviewing the previous posts in this thread I think the best solutions are:

(1) Use of new plasterboard sheeting on top of ´gypliners´(or resilient wall mounts plus furring channels), to create a non-load bearing/´floating´wall. I think this is perhaps the most effective solution, but, also the most expensive.

(2) Just cover with new plasterboard sheeting. Also effective, less expensive that option 1., but maybe has a slightly greater chance of still cracking compared to option 1.

(3) From the 2 UK posts above, and previous posts on this thread, overall I think the simplest, most cost-effective, practical and logical solution is a combination of a proper crack repair with flexible sealant and a paintable top coat (or spackle as mentioned in the 2nd UK post).

I think this is what I will try and do for this property!

The wallcovering idea is not ideal as it may wrinkle or tear.

The helibars can also be useful I think, but is better done after consultation with a geotechnical engineer.

Thanks for all contributions to this thread.

Any further comments appreciated.

GSJ