Having only mainly done renovations in houses in the UK and Ireland where plasterboard is hardly ever considered "structural" I am trying to get my head around the NZ building code and would appreciate some advice. I have read up all about gib and gibbing and gibstopping and trawled through various websites. My query is , is Gib braceline(trademark) etc. just a method of fixing standard gib or an actual product. Is it a requirement to have it done or signed off by a licensed builder. The local building inspector seems a bit vague about it.
Yes gib braceline can form bracing for the house. It is used to resit sideways loads from both Earthquakes and wind. I suspect you need a LBP designer to sign off the bracing at a minimum, or an engineer, although you should contact Gib to find out. They have calculators too to calculate bracing units required for more simple buildings that comply with NZS3604.
Braceline has fibre reinforcement / more dense core.
As well as specific fixing requirements (screw spacing, adhesive etc) there are regs about sizes and placement of penetrations, light switches etc.
Personally, I don't like it as a concept - the product is fine - better than standard gib. If external walls needed bracing, then I'd put structural ply over the framing / under the cladding. (in fact having seen what earthquakes do I'd put full ply on all external walls anyway). For internal walls, I'd design around it so it wasn't needed.
Long-term, the chances of "someone" damaging the bracing properties by poking holes in in for service fittings or alterations is high IMO. People don't think long term.
Gib of all kinds have some bracing abilities. The specific information you are looking for is what's called a Bracing Unit (BU).
Braceline is a specialised gypsum board product that has a higher BU/meter value so can provide more bracing than other kinds of Gib board. To obtain the highest bracing you need to fix it at very specific centers.
Depending on how much work is being done, and whether you are going to do it under the builder-occupier exemption, you may need to have someone do the bracing calculations for you.
Whether you need to go through the building consent process (with inspector sign-off etc) will depend on what work you are doing. Exempt building work is set out in Schedule 1 of the Building Act. You'll see that includes certain work to internal walls and wall linings, which may be relevant to what you are planning. The Ministry of Business, Innovation and Employment has a guide book with more detail. Whether or not a building consent is necessary, the building work will need to comply with the Building Code.
Edit: Sorry, I misread your question - "Is it a requirement to have it done or signed off by a licensed builder." - Detail on work that needs a licensed builder involved is here.
We had braceline put up in our recent reno, and the builder told me they had to fix it a certain way (screws, glue, no nails) and approve their work. Only goes along the inside of exterior facing walls. It's thick (13mm) and heavy too. I could see the others on site struggling and needing 2 to bring it up and attach.
Not so good for sound proofing - you still need batts in the walls and floor rafters if you're after noise deadening.
Works very well when you use steel beams as the skeleton of the house or very thick wood beams.
Not so good for sound proofing - you still need batts in the walls and floor rafters if you're after noise deadening.
That's interesting, because Braceline is the same product as Noiseline - the Gib board marketed for its ability to reduce sound transmission...
I only have Gib standard in our house, but its sound proofing is noticeably worse than the old fibrous plaster sheet wall linings that were original to the house.
The best way to use noise-line/brace-line is to use two layers each side of the framing, with staggered joints, and sealants at skirting and scotia. Batt insulation is also still recommended, but you can find some denser products with better STC ratings than glass fibre batting.
Not so good for sound proofing - you still need batts in the walls and floor rafters if you're after noise deadening.
That's interesting, because Braceline is the same product as Noiseline - the Gib board marketed for its ability to reduce sound transmission...
I only have Gib standard in our house, but its sound proofing is noticeably worse than the old fibrous plaster sheet wall linings that were original to the house.
It's optimistic to expect a big difference in noise transmission from just a change in drywall material type.
Fibrous plasterboard is nominally 1/2" thick and more dense - compared to standard 10mm Gib perhaps it's quieter. Compared to 13mm Gib Braceline or Noiseline, probably not. It's still made, but at $100 per 2400x1200 sheet, kind of expensive.
If you look at the Gib specs for noise control systems, they're using up to double layers of 13mm Noiseline, special fastening systems, batts etc for optimal performance.
donnacha: Having only mainly done renovations in houses in the UK and Ireland where plasterboard is hardly ever considered "structural" I am trying to get my head around the NZ building code and would appreciate some advice. I have read up all about gib and gibbing and gibstopping and trawled through various websites. My query is , is Gib braceline(trademark) etc. just a method of fixing standard gib or an actual product. Is it a requirement to have it done or signed off by a licensed builder. The local building inspector seems a bit vague about it.
Bracing units can be both Braceline (BL1) or standard Gib (GS1/2). They both have the same screwing pattern and restrictions on cut out sizes etc. You should get the Gib app from the app store. Having a license is still a grey area as it will need inspecting before plaster is applied but it never gets a mention in our LBP records of work.
Thanks everybody for all the replies, lots of useful information there.
On inspection the existing gib is just standard 10mm so although it is theoretically "structural" I assume I am allowed to repair it as long as I follow the recommendations by the Gib people,
i.e. use only Gib glue, Gib screws/nails, Gib board, Gib recommended screw and fixing patterns and a minimum Gib sheet size of 0.4 m.
Seems there are different levels of "structural" with Braceline being the highest level.
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