Monolithic Cement Sheet cladding mid 80s house

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Batman

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#119220 24-May-2013 17:31

Hi guys i'm struggling to get this around my head

"leaky homes" refer to homes built between 1994-2002 because of monolith cladding directly over the timber frame plus poor design (roof without eaves)

if there is a house with monolith cement cladding built in the late 80s - what is the chances of catastrophe with regards to water tightness? (note this is not art deco style)

cheers

DarthKermit

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#824894 24-May-2013 17:39

You really need a qualified builder to take a look at it to determine the correct answer.

Whatifthespacekeyhadneverbeeninvented?

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#824895 24-May-2013 17:42

I was more thinking like do i stay away or is it generally ok.

Once you sign something the lawyers have a field day.

gazbo

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#824902 24-May-2013 17:56

Short answer: More than likely has issues.

Long answer: While framing was boron treated, treatment only delays decay. The general principle of fibre cement sheet direct fixed to framing on buildings with minimal deflection of rainwater is flawed, IMHO.

Get a pre-purchase inspection from a registered building surveyor if you love the place, otherwise walk away.

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#824904 24-May-2013 18:10

Cheers. Many thanks.

So there is usually no cavity between cement sheets and timber frame?

gazbo

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#824919 24-May-2013 18:40

Cavities with fibre cement (for more than a single level simple box) were introduced in 2004.

Non rigid backed Stucco plaster (30mm cavity) and brick veneer (40mm cavity) were the only claddings that had cavity systems specified prior to 2004.

Rigid backed stucco with no cavity was the norm though.

scuwp

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#824931 24-May-2013 19:09

All homes 'leak'. Its impossible to make them completely waterproof. The issue is how the water is dealt with. Even a brick house can have a 'leaky home' problem. If the designer/builder did the job properly then there should be no issues. While I agree that some are more prone than others, I wouldn't get too caught up in the cladding type, just make sure any home you are looking at gets a full building inspection including a moisture check.

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#824946 24-May-2013 19:41

Ok cheers ... This puts my mind at rest ...

So is cement fibre the same as plaster? The same as stucco?

Also will there be insulation if there is no cavity, as according to standards all homes from 1979 must have wall insulation?

Many thanks all. Very helpful.

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#824948 24-May-2013 19:42

Yes definitely will have building inspection. But very helpful knowing which houses to shortlist and which to strike off from the start is very helpful

gazbo

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#825048 24-May-2013 22:35

scuwp: All homes 'leak'. Its impossible to make them completely waterproof. The issue is how the water is dealt with. Even a brick house can have a 'leaky home' problem. If the designer/builder did the job properly then there should be no issues. While I agree that some are more prone than others, I wouldn't get too caught up in the cladding type, just make sure any home you are looking at gets a full building inspection including a moisture check.

This is partly true, all homes leak, those with cavities manage the leaking orders of magnitude better than direct fixed monolithic.

The first problem is - How can you tell if the designer/builder did their job properly? Without cutting into the external cladding to see if water has penetrated, even a very good pre-purchase inspector is giving you an educated guess. What vendor will ever let you cut holes into their house as part of a pre-purchase?

The second thing I disagree with is that direct fix monolithic claddings are not just "more prone" to being leaky, they are systems that can not cope with leaks when they do occur because they trap water.

For example - direct fixed fibre cement sheet on untreated framing can absorb and hold enough water from rain and/or condensation to cause decay without leaking elsewhere through the cladding. This is a flawed system corrected by the DBH in 2004/5 via the acceptable solution for external moisture E2/AS1 3rd edition. The change in the acceptable solution implicitly acknowledges the flaws.

The most common type of fibre cement installed is texture coated fibre cement (TCFC e.g. Harditex or Eterpan). Along with external insulation finishing systems (EIFS - Plastered Polystyrene), these claddings were restricted to installation over cavities except to very simple single story dwellings protected with large eaves.

From 2004 there are no conditions in which direct fixed stucco is permitted, it must always have a cavity system clearly recognising this as the highest risk cladding type and responsible for the highest percentage of leaky buildings nationwide.

In terms of percentage of leaky building claims, Stucco is No. 1. TCFC and EIFS are Nos. 2 and 3 respectively.

These three monolithic claddings collectively make up 85% of all WHRS claims. If you choose to ignore these facts you will have a significantly greater risk of buying a lemon.

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#825073 24-May-2013 23:17

so if the EQC repairs says this

"Wall cladding (monolithic - cement sheet 12.96m2)"
Damage: cracking
Repair: Grind out, epoxy fill, repair stucco to affected area 0.2m2

Damage: cracking to paint
Repair: repaint wall 12.92m2

Damage: structural damage
Repair: Remove, repair and replace cement sheet 5.4m2

What do you make of the cladding?

(Note: EQC's definition of structural damage refers to one entity's structural and not the structural integrity of the house foundation/framing for example)

Thanks

gazbo

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#825077 24-May-2013 23:26

joker97: Ok cheers ... This puts my mind at rest ...

So is cement fibre the same as plaster? The same as stucco?

Also will there be insulation if there is no cavity, as according to standards all homes from 1979 must have wall insulation?

Many thanks all. Very helpful.

Fibre Cement is a composite material sheet product (same sizing as plywood generally) made from a mixture of cement reinforced with cellulose (timber) fibres. It can be painted or texture coated (plastered).

TFCF = Texture Coated Fibre Cement has a thin layer of plaster (2 - 5mm) applied to the sheets to cover the joints (similar to internal plasterboard but not smooth, textured for effect).

Stucco is also commonly known as "solid plaster" and is meant to be a 3 layered concrete skin at least 21mm thick with a metal mesh reinforcing embedded about 7 - 10 mm from the back. It can have a rigid backing (of fibre cement or ply or disastrously SSS board) or be non rigid (which must be installed over a 30mm cavity). Cavities prior to 2004 were not the drained (and hopefully vented) cavity water management systems that we have today. Often battens were installed horizontally blocking drainage planes or the cladding was closed off at the bottom trapping water.

The walls and ceiling should be insulated regardless of whether or not a cavity is installed (unless it is an EIFS system in which case the system itself may be the insulation depending on the thickness, if 40 mm it should also have batts. 60 or 80 mm polystyrene may supply R1.8 by itself and batts may not have been required). The ceiling can be checked as can the subfloor.

My advice looking at this scenario is not to view risk like a gambler i.e. simply the chance of something happening.

Instead think like an insurer:

Risk = the chance of something happening multiplied by its consequence.

The chance it is a leaky building if you go by the PWC report is around 3.5% (personally I think this is nonsense and would put this considerably higher for many reasons). The consequence however, is that you could be up for a repair cost that is between 300 - 400k (average two storey, 3-4 bedroom), and may be more than the entire property was worth in the first place. Include the fact it is far outside the 10 year limitations in both the Building and WHRS acts, there is no chance of recovering those funds via a legal claim against anyone.

That level of risk where a 400k loss is a (very roughly) 1 in 28 chance for a monolithic house is simply too high for me to contemplate. However, I understand that there is a rarer breed that have greater means and/or greater appetite for risk than I and the potential rewards may balance the risk somewhat.

Would a 400k loss break you and your family?

Do not rush. Take your time. Best of luck.

ps

Go buy a weatherboard or brick house (unless you're in Christchurch then skip brick as well).

mattwnz

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#825079 24-May-2013 23:29

Openings and balustrades, as well as parapets, if not well detailed, can leak. Especially if they are using sealants to block water. I wouldn't be surprised if houses still being built today are leaky buildings of the future.

While it is true that untreated timber is one reason leaky buildings became a problem, water should never have got to the framing in the first place. I have seen leaky bevel back weather board houses, so it is not just monolithic cladding that is the problem. Itall comes down to how it was constructed.

The other option is solid concrete block with plaster, if you like the look of the monolithic look. Also good for earthquakes, as they are reinforced concrete. I would avoid brick veneers and tile roofs if you are in an earthquake zone.

gazbo

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#825080 24-May-2013 23:31

joker97: so if the EQC repairs says this

"Wall cladding (monolithic - cement sheet 12.96m2)"
Damage: cracking
Repair: Grind out, epoxy fill, repair stucco to affected area 0.2m2

Damage: cracking to paint
Repair: repaint wall 12.92m2

Damage: structural damage
Repair: Remove, repair and replace cement sheet 5.4m2

What do you make of the cladding?

(Note: EQC's definition of structural damage refers to one entity's structural and not the structural integrity of the house foundation/framing for example)

Thanks

It actually could be either TCFC or rigid backed stucco, most likely the former though.

Were these cracks temporarily sealed after the earthquake? If not they've been leaking since then and the repairs required are likely far too light.

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#825083 24-May-2013 23:39

ok thanks for the education! (yes thinking about it the house had been absorbing water for a year and a half!)

gosh I thought leaky homes were from 1994 to 2002!

I guess the highest risk were those homes and the rest lower risk but still significant enough!

mattwnz

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#825084 24-May-2013 23:46

joker97: ok thanks for the education! (yes thinking about it the house had been absorbing water for a year and a half!)

gosh I thought leaky homes were from 1994 to 2002!

I guess the highest risk were those homes and the rest lower risk but still significant enough!

I have seen houses from the 50's- 70's that leak due to poor detailing/construction, where they aren't shedding water properly. . The NZ building code has changed, so many claddings now need a cavity. However I don't believe bevel back weather boards need a cavity, but if you use rusticated weatherboards, you do. It is perhaps why you see a lot of bevel back weather board houses being built, as it is likely to be cheaper due to no cavity being needed.
Personally if I was building a new house, I would get a cavity installed behind the cladding.