A reader's Asbestos question: Asbestos house renovation?

Kim   from   Perth W. Australia   had this asbestos house renovation question.

Hi Bill, I have an old Fibro/asbestos house which we want to tart up the outside. We will have to remove the old joining mouldings and flush the joins.

The joins have a metal weather flashing which overlaps the bottom sheet by about 12mm.

I am wondering what I can use to do the flushing in a way that wont crack a year down the track.

I have come up with using the Gyprock fibreglass mesh to go over the joint after applying some flexible compound(no more gaps type stuff) and then flushing with Gyprock cement.

I have also just had a look at some 100% acrylic roof ridge cap fixing compound I know this is for roofs, but think if I apply the Gyprock jointing mesh over the joins and then apply the elasto-max it may give a good flexible finish that should not crack easily.

We are going to paint the house with a thicker stone look paint that hides imperfections well.

Cheers and thanks

Bill's answer

Hi Kim,
I have seen the cover battens to the joints removed and flushed a few times, but never that they looked really good. It was always possible to see that it was Fibro. Most times they look worse than if they had left it alone.

  • I wouldn't use Gyprock mesh (tradesmen Gyprock flushers never use it) or any other Gyprock material externally.
  • The new replacement for Fibro is of course HardiTex, or blue board.
  • It is 7.5 thick and has recessed edges.
  • The recessed edges are the difference. They make t possible to tape and flush joint it.
  • You might want to have a look at the jointing mesh and compounds that they recommend for the joints in that system.
  • I have never seen the elasto-max stuff, it sounds like it could be too thick for what you want, but you are thinking correctly when you think flexible.
  • I have done quite a few waterproofing jobs for bathrooms. I might be tempted to try that stuff. The tape and the compound is flexible and would give only a thin layer over the joint.
  • The main problem is that once you take the cover battens off the appearance of the joint is usually fairly rough. You will have to bog the gaps up first before you lay whatever mesh you use.
  • I have done two or three cover up jobs, using horizontal custom orb cladding. That really changes the whole looks of the house, and it is not all that hard to do.
  • This is a permanent fix, but obviously more expensive.

I'd be interested to know which way you do it and what your opinions are at the end of the job, as it is a fairly common problem.
There are just so many Fibro houses out there.
Best of luck with it. Cheers

Cheers Bill for quick reply!
Yes have spoken to a James Hardie rep re Harditex system and they tell me it is just a flexible coating system that flushes the joint(no tapes used) which I find a bit suss, but it must work.

Yes you could be right about Elastomax being too thick, but will look a little further/give them a ring. The flexible is the only way to go as cracks along the joins would come all to easy a year down the track and ruin lots of work. We are selling the house but I still want to do the right thing/good job.

Funny you should mention waterproofing for bathrooms, as another product I was looking at as a contender is
they have a 100mm wide fabric that covers joints/cracks in between coats of their waterproofing coatings. They say that if using any sealants then a paintable polyurethane is recommended,.....I guess this could be used to bog the crack before applying the membrane and act as a flexible filler.

I had already done a small section using no more gaps filler and the Gyprock mesh to see how it would look and it is ok but would require feathering off the joint(to about 300mm wide) using and external filler/flushing cement to make the join less obvious/bulky.

As mentioned we would also use thicker stone look paint which also hides imperfections a little bit. I am not trying to make it look like it is not Fibro as it is what it is, but just trying to improve the over all look. We are thinking of selling in a year or so and just want a good over all finish.

We have looked at using mini orb as it looks more classy than custom orb(we think) but we are told by real estate agents not to spend too much money on the cladding as we wont get that money back.

Personally I think spending the money on metal cladding would add value but they don't think so?? I personally like it mounted vertically, but that would require batons being fixed to stud work, with boxing and flashing around windows etc(so horizontal is the easiest option)

Will let you know what I come up with and if it is coating of some sort happy to provide some pictures and feed back as it progresses and how it all looks etc.


Just another quick note to you Bill, you mentioned using the custom orb as a cover up job, so just wondering how you go getting the tech screws through 50 year old asbestos??
I have run some needle point screws through before but it is hard going with some of them and even wrecked a few tips doing so.(maybe I had dodgey screws?)
PS Hope the new year goes well for you and yours.

  • The correct screws for us up here are 14G hex head teks with neoprene washers, fixed into every second valley.
  • You would use the same I guess, but probably only 12G and maybe every third valley, you would have to check you regs.
  • There is a photo of them on my roof sheeting fixing page.
  • There is no trouble getting these in, just a good push to get them started then away they go.
  • You need a decent screwdriver gun though, you could soon burn out an underpowered one.
  • If you tried Phillips heads, I can imagine you had a few breakages.

If you are thinking of using custom orb it is definitely dearer, and will take you longer, but it will add value. The other way is just a way of putting off a permanent fix.
Your sheeting is cheap, your "U" trims and bottom flashings will probably cost more than you think, and the screws need estimating too.

It is funny, I put the asbestos page up not thinking it would be of much interest, but It is one of my top visited pages.
I have people in the US using some of my photos for teaching work health type inspectors.


If you didn't find exactly what you are looking for try this search tool that will search the site and the web.

"What can be added to the happiness of a man who is in health, out of debt, and has a clear conscience?
Adam Smith 1723-1790

"When we build, let us think that we build for ever."John Ruskin 1819-1900

coates hire
Hire Equipment
Furniture Fittings - Architectural Hardware - Electronic Locking Systems - Technical Hardware
BuilderBill sponsorship

BuilderBill Books

building maths
Building Maths

Stair Design
asbestos ebook
Asbestos Book

Calculator Pages.

Concrete yardage calculator

Reader's Questions.

Questions and answers.



Please Note! The information on this site is offered as a guide only!  When we are talking about areas where building regulations or safety regulations could exist,the information here could be wrong for your area.  It could be out of date!  Regulations breed faster than rabbits!
You must check your own local conditions.
Copyright © Bill Bradley 2007-2012. All rights reserved.
Page copy protected against web site content infringement by Copyscape