Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.
View this topic in a long page with up to 500 replies per page Create new topic
1 | 2 | 3
685 posts

Ultimate Geek
+1 received by user: 246


  Reply # 1619377 29-Aug-2016 23:18
Send private message

Aredwood:

 

I want to insulate my house. But it has Skillion roofs throughout. So no ceiling space. It was built with 150mm rafters, so I could insulate it with R3.2 batts. But would have to either lower the ceilings or raise the roof to get more than R3.2 in the roof. But would going to R4 or R5 actually make much difference?

 

House is 2 storey on concrete slab, So can't do any underfloor insulation. And currently has no insulation anywhere. Built in 1969. In Auckland so not super cold.

 

Mainly asking as I also want to replace the windows with double glazed units. So a case of spending alot more on insulating the roof, Vs spending less on the roof. And instead saving up for double glazing. Or would insulating the walls be better than getting double glazing?

 

 

I am in the same position and hope to insulate my skillion roof this summer. One thing i like to tell myself is that we some times suffer from short termism. A well insulated house is the gift that goes on rewarding the owner year after year. The building code is a minimum although in NZ we mostly aim for that point according to what you hear tradies say.

 

Ideally to answer your question, you obtain information about your existing house and put it into a heating loss calculator to determine the effect of upgrading various building features.

 

Personally, i have old pinex ceilings that are as saggy as well cooked cabbage and they're gonna go, no matter what efficiency gains might bring.

 

Have you got windows facing South?

 

If you can lower your ceiling to max out your insulation, have a look at the rails and clips system offered by your favourite plasterboard manufacturer. They add an element of decoupling so would increase noise damping as well as thermal decoupling. You might only need an extra 25 mm on top of your 150mm rafters.

 

We think about insulation at this time of year but it works in summer too ! Now there's a happy thought.


14356 posts

Uber Geek
+1 received by user: 1867


  Reply # 1619379 29-Aug-2016 23:43
Send private message

elpenguino:

 

Aredwood:

 

I want to insulate my house. But it has Skillion roofs throughout. So no ceiling space. It was built with 150mm rafters, so I could insulate it with R3.2 batts. But would have to either lower the ceilings or raise the roof to get more than R3.2 in the roof. But would going to R4 or R5 actually make much difference?

 

House is 2 storey on concrete slab, So can't do any underfloor insulation. And currently has no insulation anywhere. Built in 1969. In Auckland so not super cold.

 

Mainly asking as I also want to replace the windows with double glazed units. So a case of spending alot more on insulating the roof, Vs spending less on the roof. And instead saving up for double glazing. Or would insulating the walls be better than getting double glazing?

 

 

I am in the same position and hope to insulate my skillion roof this summer. One thing i like to tell myself is that we some times suffer from short termism. A well insulated house is the gift that goes on rewarding the owner year after year. The building code is a minimum although in NZ we mostly aim for that point according to what you hear tradies say.

 

Ideally to answer your question, you obtain information about your existing house and put it into a heating loss calculator to determine the effect of upgrading various building features.

 

Personally, i have old pinex ceilings that are as saggy as well cooked cabbage and they're gonna go, no matter what efficiency gains might bring.

 

Have you got windows facing South?

 

If you can lower your ceiling to max out your insulation, have a look at the rails and clips system offered by your favourite plasterboard manufacturer. They add an element of decoupling so would increase noise damping as well as thermal decoupling. You might only need an extra 25 mm on top of your 150mm rafters.

 

We think about insulation at this time of year but it works in summer too ! Now there's a happy thought.

 

 

 

 

Many skillion roofs have high windows up to the ceiling, so lowering the ceiling is often not an option. Also doing so can reduce the greater feeling of space they offer. I have seen a house where they decided to replace a skillion ceiling with a 2.4 metre flat ceiling. Looked terrible and ruined the design, and probably knocked a lot off the value of the house.




3122 posts

Uber Geek
+1 received by user: 1210

Subscriber

  Reply # 1619383 30-Aug-2016 00:50
Send private message

@froob

 

Thanks for those links. The first one especially confirmed that what Im planning to do would be OK. As I don't have any of the other risk factors mentioned. If my roof was plywood with a membrane on top then I would be worried. Requiring that air gap is the article writers means of butt covering.

 

@Disrespective

 

Very interesting calculator. It said that using the R4.4 would end up with a total R value of 3.71. But that calculator was assuming that the rafter edges had no insulation on them. The rafter edges in my house will be covered with the R1.2. Sure I won't get the entire R4.4 But using the extra R1.2 means I will get at least R3.71 overall. And with the rafter edges covered, I should be able to get approx R4 overall.

 

Without using the extra R1.2, The overall is R2.99. So only just above the current min required. So the extra R1.2 is definitely worth it.

 

I even managed to get a scenario where the total was R 4.71. But that was getting the insulation coverage to 100% Which would be impossible in reality as that would require a roof that has no framing timber whatsoever in it.

 

@neb

 

Thanks for the tip about Knauf. Since they also offer glasswool. So far, from what I have seen. Almost every other type of insulation requires a larger thickness to achieve the same R value. Which is no good for me due to my lack of roof space.

 

 

 

For those who suggested lowering the roof space - I like the cathedral / skillion type ceilings. Partly due to the extra sense of space, And partly as you have more choice of lighting - You can easily have pendant type lights. And due to the size of the lounge - it would feel really cramped if I lowered the ceiling to 2.4m.

 

Although in the lounge, the rafters are exposed. Rest of upstairs they have been gibbed over. So I would have to gib over the lounge rafters no matter what.

 

And if I ever buy a projector - the cathedral ceilings mean a much larger screen size is possible.

 

But the biggest problem with the lounge is that the previous owners extended it in the 80s by adding on a conservatory. It can't be closed off from the rest of the house. It means the lounge is like a greenhouse. So stupidly hot in summer, stupidly difficult to heat in winter. And everything else about it is stuffed. The piles on it are sinking, water in leaking into the particle board flooring, the door to outside is out of square, it is draughty ect. So the only proper fix for it is to demolish and rebuild with proper walls, roof ect.

 

Which will cost really big $$$ as it would also include a new Kitchen and Laundry. I had previously relocated the kitchen there to make more space in the lounge, And the laundry to the little covered deck next to the conservatory to move it out of the garage. The kitchen how it is currently is far more functional compared to the old kitchen. Despite it being bodged together out of part of the kitchen installed by the same 80s owners. And part from a Bar that was removed from a friends flat. (One of the flatmates from that flat was a cabinetmaker, who built a bar on the deck of that flat. Which they had to remove when they all moved out of that place.)

 

 






1797 posts

Uber Geek
+1 received by user: 120


  Reply # 1619394 30-Aug-2016 06:35
Send private message

Mammoth do a polyester insulation which will cost you a bit more, but has better r values in the same thickness. It might be worth considering if max r value is important.

14152 posts

Uber Geek
+1 received by user: 2546

Trusted
Subscriber

  Reply # 1619402 30-Aug-2016 07:27
Send private message

I'd be talking to a building inspector or similar. If you remove the air gap it could be reported as a "potentially leaky home" if you go to sell it, assuming they can get access to see it.





AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer


7752 posts

Uber Geek
+1 received by user: 2559

Subscriber

  Reply # 1619405 30-Aug-2016 07:36
Send private message

Disrespective: Mammoth do a polyester insulation which will cost you a bit more, but has better r values in the same thickness. It might be worth considering if max r value is important.

 

 

 

no it doesn't. an example, Mammoth 105mm skillion R2.9 vs Earthwool 105mm skillion R3.2. Same deal for the walls. there is about R0.3 difference for the same thickness for the wall sections


2545 posts

Uber Geek
+1 received by user: 340


  Reply # 1619434 30-Aug-2016 09:10
Send private message

Won't this insulation make the Aredwood brand heating system redundant?

880 posts

Ultimate Geek
+1 received by user: 774

Trusted
Chorus

  Reply # 1619496 30-Aug-2016 09:45
One person supports this post
Send private message

I wrote a lengthy post on my experience on this but when I went to add photos my Firefox crashed and I lost the lot. Probably just as well - the post was too long anyway lol.

 

Having said that, I just insulated my skillion ceiling last week. I had 140mm of exposed rafters below the ceiling linings, but there was no space between the lining and corrugated iron roof to install insulation into. So I bought Earthwool R3.2 ceiling blankets, cut them to shape, and installed them between the rafters below the existing ceiling lining, and strapped them up. I bought GIB cheaply from my friend in the trade, and late last week my plasterer installed the GIB, and is finishing the stopping today.

 

The difference to warmth in my lounge has been instant and measurable. Prior to this, I was running my heatpump at 25 degrees 24 hours a day and the whole house was still freezing. Was costing me a bomb too. The last few days I have had the heatpump set to 18 degrees at night, and I switch it off during the day, and the house is very toasty.

 

I ended up insulating the west wall of my lounge at the same time, as I wanted to install additional power sockets and cabling to mount my tv on the wall. The rest of my walls are uninsulated so I'll eventually do each room one at a time as my budget allows.

 

In a few weeks I'll be having an ultra low emission log burner and heat transfer kit installed. I really can't wait for that!

 

Here's what my place looked like last week:

 

 

 

 

And what it looks like today:

 

 

I estimate by the time I  am finished I will have spent around $3000 (on insulation - $600, GIB - $350, plasterer - $1300, and painter - $ unknown). I am sure I saved a bit by cutting and installing the insulation myself. The area of skillion ceiling I have insulated is roughly 40 square metres. The rest of the house has standard ceilings with plenty of ceiling insulation to those areas.


6725 posts

Uber Geek
+1 received by user: 592

Trusted

  Reply # 1619514 30-Aug-2016 10:19
Send private message

Good stuff!


5134 posts

Uber Geek
+1 received by user: 2092


  Reply # 1619533 30-Aug-2016 10:50
Send private message

Nice work.





Mike

880 posts

Ultimate Geek
+1 received by user: 774

Trusted
Chorus

  Reply # 1619535 30-Aug-2016 10:52
One person supports this post
Send private message

What about this guy??? Creepy much?

 

 

 


92 posts

Master Geek
+1 received by user: 61


  Reply # 1619578 30-Aug-2016 12:03
One person supports this post
Send private message

froob:

 

 

 

I expect you've read up on this and considered the options, but the recommendation seems to be for a 25mm air gap between the roof underlay and insulation. Here are a few examples:- 

 

- http://www.buildmagazine.org.nz/articles/show/keeping-skillion-roofs-dry/

 

- http://www.buildmagazine.org.nz/articles/show/retrofitting-insulation/

 

- http://www.level.org.nz/passive-design/insulation/options-for-roof-insulation/

 

- https://www.energywise.govt.nz/at-home/insulation/ceiling-insulation/insulating-skillion-or-flat-roofs/

 

I can't give you any indication on how important the air gap is, but for myself, I would be taking the more cautious approach in line with those recommendations. I'm by no means an expert on the matter however.

 

It is true that there are plenty of houses out there with direct fixed cladding and insulation without problems, but there are also plenty that do have problems with moisture, which is why insulating exterior walls requires a building consent. Roofs are presumably considered less risk as (I understand) insulating them is exempt from the building consent requirement (as you mentioned), even for a skillion roof. The work still needs to meet code though, and a good way of doing that for the uninitiated (such as myself) is aligning with industry guides like those above.

 

 

Its important to have a gap between the roof underlay and the insulation. Otherwise you have a direct path for any moisture to flow into the ceiling space. Just like touching the flysheet on the inside of a tent in the morning.


685 posts

Ultimate Geek
+1 received by user: 246


  Reply # 1619640 30-Aug-2016 13:05
Send private message

Wheelbarrow01:

 

And what it looks like today:

 

 

Awesome, totally jealous.

 

Did you use standard 2.4m gib? How did you hold it up for screwing/glueing?


880 posts

Ultimate Geek
+1 received by user: 774

Trusted
Chorus

  Reply # 1619676 30-Aug-2016 13:55
Send private message

elpenguino:

 

Wheelbarrow01:

 

And what it looks like today:

 

 

Awesome, totally jealous.

 

Did you use standard 2.4m gib? How did you hold it up for screwing/glueing?

 

 

I used standard 10mm GIB in various lengths. If you want to save a bit of money you can opt for standard plasterboard (ie not a GIB product). It's cheaper and I believe the quality is pretty much the same. Architects and quantity surveyors etc tend to specify the brand name GIB on their plans, meaning you must use GIB in those instances where council signoff is required (ie new builds). I can only assume the architects get a kick-back from GIB for this. It's a contentious issue which I have read about elsewhere as one of the reasons build costs are so high in NZ. For renovations there is absolutely nothing stopping you from using a cheaper product and the result is the same. I have used non GIB products in the past with success. I only used GIB brand on this occasion because a friend in the trade got it for me at cost price.

 

In terms of holding it up prior to screwing, I recommend a plasterboard lift. My plasterer bought one for around $400 and he said he couldn't do without it now, but the one I linked to is even cheaper than that. I would have put the GIB up myself using one of these lifters but I hurt my back recently so paying my plasterer to do it was the sensible way to go this time. In the end he did it way faster than I could have done anyway - all 40 square metres was up in one day.

 

When my wall linings were off I took the opportunity to install additional power, ethernet, aerial, Sky and HDMI cables/sockets so that when I mount my tv on the wall, all the cables will be invisible.

 

I'll post another photo tonight - the second coat of plaster should be on by the time I get home, so apart from painting I am in the home stretch.


5134 posts

Uber Geek
+1 received by user: 2092


  Reply # 1619747 30-Aug-2016 15:50
One person supports this post
Send private message

Wheelbarrow01:

 

Architects and quantity surveyors etc tend to specify the brand name GIB on their plans, meaning you must use GIB in those instances where council sign-off is required (i.e. new builds).

 

That practice ... should be illegal for something as generic as plasterboard. 

 

Should be specified as something like ... plasterboard conforming to standard NZSxxx





Mike

1 | 2 | 3
View this topic in a long page with up to 500 replies per page Create new topic

Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.