suddenly non GIB boards are approved for use

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2393 posts

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#2949773 2-Aug-2022 17:02

evilengineer:

There's also "Ecoply Barrier" by CHH (plywood) and IBS Rigid Rap (OSB) available on the market with BRANZ/Codemark bracing ratings as well.

Also, fairly certain you don't need an extra building wrap on top of these Ply/OSB products as long as the sheet joints are properly taped as per the installation manuals.

some ply/osb products come with the wrb glued onto them, therefore no need for any extra wrb/building wrap. those without need building wrap etc installed. it also pays to check what the permeability of the product is. there can be a big difference depending on what wrb product is glued to it. you also need to have the suitable tape or liquid flashing products that will bond to it and other building materials like concrete. some tapes require primers, some are pressure activated, so there can be a big difference in how they are installed and on what.

tweake

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#2949777 2-Aug-2022 17:20

MikeAqua:

tweake:

blue gum, o thats nice 😍

with RAB consider going the whole hog and making it fully air tight. its not as hard as many make it out to be. i'll find some links about that.

insulation wise, unless its double story, its worth mentioning 4" wall with 2" external insulation. trade a bit of building strength for better insulation and increased durability compared to 6" walls.

The gums are growing on the property and will be milled just down the road. I think they'll look good. They're very straight with enough small branches to ensure a bit of figure.

I'll look into the sealing up. I'll be doing a lot of the tedious parts of the building, so we can afford to do labour intensive stuff like that.

I need the wall depth for the format of windows that I want.

I'm note sure about insulating with foam outside the cladding. We're leaning towards a large stone block type cladding.

yes air sealing is tedious. however that can be reduced by limiting the amount of penetrations through the rab and cladding. you have to plan ahead and make sure you have locations for everything. last thing you want is tv guy drilling a hole through the wall to put a tv cable in. or worse still heat pump guy. once the cladding is on there is no way you can get in and seal any new holes through the wall.

external insulation is inbetween the exterior block and the wooden wall. fastened to the wooden wall, actually on the RAB. ie the layers is wooden wall, rab, insulation, air gap, brick cladding. i do not recommend foam insulation as its higher risk. i prefer something like rock wool that has high permeability so your not stopping moisture and possibly have it build up. lower risk for nz wet/humid climate. the advantage of external insulation is the wood is not directly exposed to outside temps, so its kept warmer which makes it more durable. plus its stops a lot of the thermal bridging, ie not loosing heat through all the wood exposed to outside temps.

Handle9

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#2949801 2-Aug-2022 18:03

@tweake could you please use capital letters at the start of a sentence? You have good things to say but your posts are very difficult to read.

neb

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#2949812 2-Aug-2022 18:15

Handle9: @tweake could you please use capital letters at the start of a sentence? You have good things to say but your posts are very difficult to read.

a total stranger one black day

knocked living the hell out of me—

who found forgiveness hard because

my(as it happened)self he was

-but now that fiend and i are such

immortal friends the other's each

--- e e cummings

mattwnz

20169 posts

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#2949813 2-Aug-2022 18:17

tweake:

yes air sealing is tedious. however that can be reduced by limiting the amount of penetrations through the rab and cladding. you have to plan ahead and make sure you have locations for everything. last thing you want is tv guy drilling a hole through the wall to put a tv cable in. or worse still heat pump guy. once the cladding is on there is no way you can get in and seal any new holes through the wall.

That is often difficult as tradies jump between jobs and may not be onsite at a particular time, or have the time to do it in time. . I have seen tradies have to cut into flooring, gib etc when they have forgotten to put in services in some areas.

tweake

2393 posts

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#2949816 2-Aug-2022 18:22

Handle9: @tweake could you please use capital letters at the start of a sentence? You have good things to say but your posts are very difficult to read.

Sorry, English is my third and only language. My grammar and spelling is terrible, and most capitals are in because that's what the spell checker puts in. (and thats 6 spelling errors already)

Handle9

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#2949824 2-Aug-2022 18:38

tweake:
Handle9: @tweake could you please use capital letters at the start of a sentence? You have good things to say but your posts are very difficult to read.

Sorry, English is my third and only language. My grammar and spelling is terrible, and most capitals are in because that's what the spell checker puts in. (and thats 6 spelling errors already)

Thank you :)

Sharesies

Trade NZ and US shares and funds with Sharesies (affiliate link).

tweake

2393 posts

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#2949827 2-Aug-2022 18:44

mattwnz:

tweake:

yes air sealing is tedious. however that can be reduced by limiting the amount of penetrations through the rab and cladding. you have to plan ahead and make sure you have locations for everything. last thing you want is tv guy drilling a hole through the wall to put a tv cable in. or worse still heat pump guy. once the cladding is on there is no way you can get in and seal any new holes through the wall.

That is often difficult as tradies jump between jobs and may not be onsite at a particular time, or have the time to do it in time. . I have seen tradies have to cut into flooring, gib etc when they have forgotten to put in services in some areas.

but it can be done. if you accept defeat from the start you will never get it done right. employing good trades that will do the right job is key. but also checking that they have done it right and paying them what its worth. good planning, checking everything did get put in, making sure the air sealing boots are there etc. also providing locations they can use that can seal up later.

the other thing is do to tradie friendly design. one thing i like, from an ex-tradie perspective, is the conditioned crawlspace and attic concept. you can run services anywhere under the floor and above the ceiling easily, without putting any holes through the exterior/air barrier/thermal barrier. you only have to worry about the few that go through the walls and roof. if you need another power outlet, not a problem as the floor and gib are not air barriers.

in my experience most of the problems are because the build is planned poorly and things get left out. part of that is builders/home owners don't understand of whats required to do the job properly. one common thing is having one tradie do multiple trades.

MikeAqua

7785 posts

Uber Geek

#2950714 4-Aug-2022 16:35

tweake:

yes air sealing is tedious. however that can be reduced by limiting the amount of penetrations through the rab and cladding. you have to plan ahead and make sure you have locations for everything. last thing you want is tv guy drilling a hole through the wall to put a tv cable in. or worse still heat pump guy. once the cladding is on there is no way you can get in and seal any new holes through the wall.

external insulation is inbetween the exterior block and the wooden wall. fastened to the wooden wall, actually on the RAB. ie the layers is wooden wall, rab, insulation, air gap, brick cladding. i do not recommend foam insulation as its higher risk. i prefer something like rock wool that has high permeability so your not stopping moisture and possibly have it build up. lower risk for nz wet/humid climate. the advantage of external insulation is the wood is not directly exposed to outside temps, so its kept warmer which makes it more durable. plus its stops a lot of the thermal bridging, ie not loosing heat through all the wood exposed to outside temps.

The advantage of a lot of DIY input, is that I will be able to make sure things are done right, rather than the usual approach of "stuff the customer, I'll do whatever is easiest for me". Because of the insulation type I'm using, I'll be putting in conduit for future services or services that may need re-running e.g. network cables, home theatre cabling etc.

I'm not sure I'll need external insulation. I'll be going with spray on foam (PU) and with 140mm framing, there is going to be plenty of R. Also, if you have insulation between the RAB and the blocks, how to secure the blocks to the frame with ties? These will be stone or mud blocks.

Mike

mattwnz

20169 posts

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#2950720 4-Aug-2022 16:42

Look like the gib crisis is now over https://www.stuff.co.nz/business/129468354/gib-shortage-over-due-to-construction-industry-slowdown

mattwnz

20169 posts

Uber Geek

#2950722 4-Aug-2022 16:46

MikeAqua:

The advantage of a lot of DIY input, is that I will be able to make sure things are done right, rather than the usual approach of "stuff the customer, I'll do whatever is easiest for me". Because of the insulation type I'm using, I'll be putting in conduit for future services or services that may need re-running e.g. network cables, home theatre cabling etc.

Sounds like you have built before. My motto is if you want something doing properly and well, do it yourself. Homewoners have more time to do it well. Some people don't have the skills or knowledge to do it themselves, but quite a few people do. But with insulation, I also make sure it is stapled to the surrounding timber structure to reduce the risk of it sagging or slumping. Wool insulation especially.

tweake

2393 posts

Uber Geek

#2950725 4-Aug-2022 17:08

MikeAqua:

I'm not sure I'll need external insulation. I'll be going with spray on foam (PU) and with 140mm framing, there is going to be plenty of R. Also, if you have insulation between the RAB and the blocks, how to secure the blocks to the frame with ties? These will be stone or mud blocks.

Open or closed cell? Be aware of the permeability. Some outfits are advertising none-permeable foam which is not good with wooden walls.

Also there is the "flash and batt" setup where they use spray foam against the RAB then a layer of batts. Thats to keep costs down.

With external insulation, the block ties are done as per normal, just longer ones required, and the insulation is fitted around them.

tweake

2393 posts

Uber Geek

#2950726 4-Aug-2022 17:12

mattwnz:

Look like the gib crisis is now over https://www.stuff.co.nz/business/129468354/gib-shortage-over-due-to-construction-industry-slowdown

Not surprising. Many home owners have been building new because they could push the cost down the ladder onto FHB'ers. Now they have been squeezed for every last cent, the ladder is starting to fall over.

MikeAqua

7785 posts

Uber Geek

#2952399 9-Aug-2022 10:59

tweake:

Open or closed cell? Be aware of the permeability. Some outfits are advertising none-permeable foam which is not good with wooden walls.

Closed cell, two part PU foam.

Mike

tweake

2393 posts

Uber Geek

#2952662 9-Aug-2022 18:12

MikeAqua:

tweake:

Open or closed cell? Be aware of the permeability. Some outfits are advertising none-permeable foam which is not good with wooden walls.

Closed cell, two part PU foam.

Just be aware that closed cell is non-permeable which makes it higher risk, because it stops moisture flow.

A common twist is to spray 2" foam, 4" batts. That also give the timber a lot more surface area to dry into the home and reduces cost, not to mention easier on plumbing/electrical. but its still a moisture barrier to the house.

If you really want to fit a moisture barrier, you should put it between the wooden wall and the brick. look up "the perfect wall" concept.

But, in our climate we don't need moisture barriers and its less risky to not have them when you don't need them. To quote one of the great building scientists, "better to not have a moisture barrier than to have one in the wrong place". Hence why we use permeable insulation, let it dry in any direction.

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