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Timber House retrofit - wall profile

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Started 7 years ago by ankerre
Latest reply from jones23

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ankerre
Member

Hi, We have a small timber house / high country / north east Victoria. Existing walls have insulation zero so everything we do is an improvement! Proposed wall profile is plaster board, 90mm R2.0 batts, sisilation, timber battons, galvanised corrugated iron. Windows are triple glazed. (Floor is timber with foilboard (15mm, 19mm chipboard, cork tiles). Floor will butt up to and marry with wall insulation treatment.

We want to explore alternative and additional insulation, so the specific wall batt, the quality of the sisilation / builders wrap and any additional product which could enhance the R rating is presently what we are looking for. We have building approval with an energy rating so any additional will be fine.

Any one with any comments on this.

Posted Friday 10 Jan 2014 @ 4:34:23 pm from IP #
dave lawrence
Member

do you intend to remove existing wall linings and or cladding ?
because if you do , why not pack out 90 mm studs to increase their thickness to say 120-140 mm ,allowing greater depth for min. R3.0 insulation ?

Posted Friday 10 Jan 2014 @ 7:28:08 pm from IP #
ankerre
Member

Hi Dave, thanks for response. Your suggestion is possible. Exterior cladding is all removed (was asbestos) & is just presently wrapped in builders paper. In some areas plaster has also been removed due to poor condition. so, I could increase wall profile - curious as to most economic way to do so. Would a layer of Thermotech (or equivalent) before battons increase R rating?

Posted Friday 10 Jan 2014 @ 9:54:44 pm from IP #
dave lawrence
Member

yes, pack out studs , say 30mm ,then RFL sarking over that ,then 30 thick battens over that then cladding.thay way the 30 mm airgap allows sarking to work more effectively than the way its mostly donei n australia ,which is to have cladding hard up against sarking .this is also konwn as "rain screen cladding" ,and is common practice in countries with more advanced framed building construction .(i.e most other developed countries ).
you then end up with 120 mm thick stud, insulated between studs to min R3.0 ,refrlective sarking ,airgap and then cladding.

Posted Sunday 12 Jan 2014 @ 10:08:38 am from IP #
ankerre
Member

Thanks again Dave. WRT the flooring, we have removed previous hardwood floor, dug out to improve ventilation down to 400mm or so, and have a 15mm foil-board system to go into joists using plastic clips to produce an even airlock, then a 19mm chipboard floor and new generation cork floor over the chipboard which will marry to whatever treatment goes to the wall profile. This we expect to deliver reasonably high insulation qualities. However, I do see a potential problem in getting joins working well; walls with floor, windows with walls, walls with ceiling. Any thoughts you or others have on ensuring that this weak point can be addressed is appreciated.

Posted Sunday 12 Jan 2014 @ 11:14:24 am from IP #
dave lawrence
Member

don't rush the builder, lots of the time the problem lies in the fact that jobs are simply rushed and not done properly. by taking your time you increase chances of tight fitting seals etc.

Posted Monday 13 Jan 2014 @ 7:36:08 pm from IP #
ankerre
Member

Thanks again for the contribution. the existing studs are closer to 70mm hardwood and I assume that we can thicken them with adding say 50mm on top of that rather than purchase all new pine studs. Alternatively, if we replace the 70mm with pine 90mm, add a treatment/layer of foilboard say 100mm over the studs (studs will include wall batt), seal with sarking and then complete with a batton to support the galvanised iron. I assume this could be overkill but taking time to get seals right should work well. comments welcome.

Posted Monday 13 Jan 2014 @ 7:59:37 pm from IP #
axess
Member

Hi Ankerre,
You are absolutely correct in focussing on high levels of insulation and meticulous attention to draght sealing given your location.
It might be worth a visit to the websites of the major insulation suppliers like Kingspan, Bradford, CSR, Wren, Foilbooard, etc. They are familiar with layers used in combination to achieve the best results and often have products that are new to the industry.
One issue I can understand the builder being wary of is the final wall thickness deviating too much from standard. This will affect the linkages with other building elements (roof and floor connections, and window and door reveals to some extent) and has to be considered carefully in an existing timber framed building. Naturally these solutions can be designed into a new building more easily.
Be very carefull how you combine wraps and insulation systems when designing for a cold climate because of the need for moisture control. Permeable layers can trap moisture rather than allowing dissipation and this can lead to other problems further down the track.
You are definitely on the right track so good luck with your project.

Posted Monday 13 Jan 2014 @ 9:00:50 pm from IP #
dave lawrence
Member

axess said ...
" One issue I can understand the builder being wary of is the final wall thickness deviating too much from standard. This will affect the linkages with other building elements (roof and floor connections, and window and door reveals to some extent) and has to be considered carefully in an existing timber framed building."
I agree with that statement , but that does not mean you should not increase the wall thickness. If interested in rainscreen details and advanced framing techniques PM me.

Posted Monday 13 Jan 2014 @ 10:43:31 pm from IP #
cedar ray
Member

Hi ankerre.
Couple of thoughts.Any packing to increase stud depth, as suggested,should be on the outside/ inside will reduce room size.Reflective foil should have an air gap BOTH sides.If you put R/foil onto studs, it will be in contact with the bulk insulation. Not good. I have done similar but I am in central Vic. hotter climate so operation of foil was more important to me.
I used battens(19mm)on outside of studs. This held bulk insulation in place and provided air gap.Then foil(double sided Wren). Next, second run of battens to fix outer cladding to. The first run of battens need to be horrizontal and second run vertical. Note that this means you run your corry iron horrizontal, which most prefer for a house anyway, vertical tends to be "shed" looking. Your choice.If you prefer vertical cladding ie.mounting battens horizontal, then a layer of building wrap/sizelation or anything really, just to support the bulk insulation, can be applied to the studs to prevent contact with the foil. Then battens, foil, battens.Confused? Just draw a diagram and hopefully it will become clear. Also make sure that the outer battens are fixed right through to the studs. Don't want the cladding blowing off in a wind! Due to my climate being hotter here, I used foil batts in the ceiling as well. Mine was just a reno, so I still have some single pane windows which allow most of the heat through but on a 40deg. day, both ceiling and Nth.facing wall are cool to the touch.
axess is right about moisture control, very important in a cold climate. Also window and door reveals but some creative planning will produce a result that still looks good. Good luck with the project.

Posted Tuesday 14 Jan 2014 @ 1:14:00 am from IP #
dave lawrence
Member

as previously offered ,I have lots of details pertaining to battening out studs, and you can actually pack a wall out on the inside, yes it reduces room size ,but it all depends on the room size . moisture ingress is FAR LESS LIKELY IF CORRECTLY DETAILED with rain screen cladding done PROPERLY,by desiging for CAVITY drains, just as cavity masonry walls have. ADJUSTING door and window frames to the new IMPROVED WALL FRAME THICKNESS is easy too and offers the possibility of beautiful thick sills... think window seats .
But I agree, if the rooms are not generous sized already ,it will be an easier and better option to just pack out the external side ,me personally I would opt for 35 thick battens, NOT 19 , but any thing you choose to do will be an improvement, if done properly .

Posted Tuesday 14 Jan 2014 @ 6:02:07 am from IP #
dave lawrence
Member

I also agree that the RFL needs to NOT be in contact with bulk insulation .

Posted Tuesday 14 Jan 2014 @ 6:03:24 am from IP #
ankerre
Member

Thanks everyone for inputs. Regarding the RFL potentially contacting the bulk insulation, I thought that I had seen many examples of where a house has stud walls / with RFL dressed on the outside and then the batts are pushed up against it from the inside before the plaster board goes on. Are you saying that this causes problems with condensation? If so, then I imagine one way around it would be to put a plywood surface before the batts, which I think I have also seen but not investigated. I will give this some thought. On the issue of Batts, I understand that Pink batts are now banned in the USA due to installers haveing problems - so is the Tontine batt a good compromise? Cheers.

Posted Tuesday 14 Jan 2014 @ 6:38:30 am from IP #
tom
Member

What is the cladding going to be? (Sorry if I missed it). Could you use a rendered foam panel? (Masterwall 80mm K-series is R4).

For insulation batts, the Earthwool batts sold at Bunnings are made from recycled bottles and are cheap.

Posted Tuesday 14 Jan 2014 @ 9:09:52 pm from IP #
ankerre
Member

Tom - cladding is galvanised iron, house is timber. Did not realise I could use a rendered foam panel but maybe not on this house. Regarding batts, thanks for the info - I assume from what you are recommending here that the different constituents of batts effect the acoustic as well as insulation values; recycled bottles etc has a higher density perhaps?

Posted Wednesday 15 Jan 2014 @ 7:10:32 pm from IP #
tom
Member

Not really suggesting they are better or worse than other batts. They are made from recycled stuff, so that is a plus in my book. Plus they are cheap. All 90mm batts will be R2.5, regardless of the material they are made from. If you want the best sound insulation, then Rockwool is what you want.

Posted Wednesday 15 Jan 2014 @ 8:30:23 pm from IP #
ankerre
Member

Thanks again to all for valuable advice. We also have two bedrooms adjacent living area, so wanted to look at dampening to lessen impact or sound proof the room. We saw reference to the use of Felt for this on one posting. Can felt be combined with poly batts to cut down on noise penetration? We have felt that can be recycled but not keen to do it if there is negligible impact.

Posted Thursday 16 Jan 2014 @ 1:59:17 am from IP #
axess
Member

Hi ankerre,

You could aim to interrupt the transmission of sound through the wall by incorporating an acoustic break- discontinuing the transmission of sound waves that travel through solid elements such as wall studs, noggins and battems. It's similar to thermal breaks in aluminium framed windows. Your felt for example could be used as washers, shims or packers between the elements.

Another route (or in combination with)is to bump up the plasterboard spec by using specialty boards or thicker boards or multi-thickness layers. Some methods also include a specialty compound that claims to achieve results by used a product applied by cartridge (similar to applying silicone). "Green glue" for example.

Here is a link to the Gyprock site but all of the suppliers offer similar solutions:

http://www.gyprock.com.au/Pages/Products/Plasterboard/Soundchek.aspx

Batts alone don't seem to do it in our house unfortunately!

Good luck.

Posted Thursday 16 Jan 2014 @ 2:28:20 am from IP #
ankerre
Member

Thanks axess, so, I take it the Tontine sound batts are not worth the investment if it is sound abatement you want? Do you need to go for multiple layers of the Gyprock or will one have impact? Can any medium like a felt also help? cheers.

Posted Friday 17 Jan 2014 @ 6:54:02 am from IP #
Eamon
Member

To avoid moisture in your walls, always maintain an even traveling air gap. Dense (not thick) insulation will give you added sound barrier, so too will isolating the external sheet or cladding from the main structure. Here is a professional example process of sound and good insulation process. http://www.asc-soundproof.com/iso-diagrams.htm All similar materials are accessible in Aus.

Posted Tuesday 21 Jan 2014 @ 1:26:06 pm from IP #
Greg
Member

Not all 90mm batts are the same R value. From my research the polyester batts were lower R value for a given thickness than say recycled glass batts. I managed to obtain knauf batts at a good price which from their literature are very safe and offered good insulation ( the price was the determining factor for me ).
Can I ask what thermal mass you will have inside the house. Insulation is great but thermal mass stores and thereby regulates the heat flow which helps maintain an even temperature. Esky's dont work well without thermal mass.

Posted Thursday 23 Jan 2014 @ 6:05:38 am from IP #
ElizebethWoodhall
Member

I agree with Eamon, such nice suggestion to avoid moisture. Ankerre you must follow this while re-construction as moisture will lead to mould in insulation specially if its foam insulation. You can get expert opinion from http://insulationremoval.ca/. I personally have good experience with them!

Posted Friday 24 Jan 2014 @ 8:57:24 am from IP #
Morbo
Member

I would recommend white colorbond walls. As the gal looses its shininess, absorptivity goes up and white will do better in the long run.

For thermal mass, put more stumps in. Then get stone benchtop and what not. All that ceramic stuff in our kitchen stores heat and cold for quite some time.
Get two layers of plaster board or better FC sheet as thats more robust.

Also, instead digging underneath the house and by this putting it into a pond (so rainwater wants to get underneath the house) why not just lift it up? Not much to it, got mine restumped/relevelled, only takes a few bottlejacks. And you want to gut your house anyway, no need to worry about cracked plasterboard.

Posted Friday 24 Jan 2014 @ 10:11:42 am from IP #
ElizebethWoodhall
Member

Morbo said:
Also, instead digging underneath the house and by this putting it into a pond (so rainwater wants to get underneath the house) why not just lift it up? Not much to it, got mine restumped/relevelled, only takes a few bottlejacks. And you want to gut your house anyway, no need to worry about cracked plasterboard.

Will it help in avoiding moisturizing of walls ?

Posted Friday 24 Jan 2014 @ 12:24:25 pm from IP #
ankerre
Member

Cannot use Colourbond due to Heritage requests from Council and we can live with that. Will follow the ventilation advice and note the importance viz the Canadian evidence thanks to Elizebeth. For interior walls we have been looking to deaden sound between rooms and one suggestion is to use a layer of MDF on back of existing plaster, then Rockwool (50mm) and then Gyprock soundcheck for the new surface. The Rockwool promotes itself as being resistant to mould - and we had no references when trying to compare it to Knauf products / Earthwool - it looks to be very similar. As we don't anticipate any moisture issues on the inside of the house it all should be fine. Any comments on the use of MDF as a sound retardant?

The underfloor insulation is not easy in some areas due to lack of clearance, but after much discussion the Air-cell / Kingspan product stapled to the bottom of joists seems a very good compromise. We had looked at styrene with the pre-cut lines through it but in a tight space there is difficulty in getting the pieces inserted and then rodents are apparently keen on utilizing the material. We understand that the Air-cell needs to be a tight fit, to form an unventilated space.

Posted Friday 24 Jan 2014 @ 9:19:43 pm from IP #
ankerre
Member

Cannot use Colourbond due to Heritage requests from Council and we can live with that. Will follow the ventilation advice and note the importance viz the Canadian evidence thanks to Elizebeth. For interior walls we have been looking to deaden sound between rooms and one suggestion is to use a layer of MDF on back of existing plaster, then Rockwool (50mm) and then Gyprock soundcheck for the new surface. The Rockwool promotes itself as being resistant to mould - and we had no references when trying to compare it to Knauf products / Earthwool - it looks to be very similar. As we don't anticipate any moisture issues on the inside of the house it all should be fine. Any comments on the use of MDF as a sound retardant?

The underfloor insulation is not easy in some areas due to lack of clearance, but after much discussion the Air-cell / Kingspan product stapled to the bottom of joists seems a very good compromise. We had looked at styrene with the pre-cut lines through it but in a tight space there is difficulty in getting the pieces inserted and then rodents are apparently keen on utilizing the material. We understand that the Air-cell needs to be a tight fit, to form an unventilated space.

Posted Friday 24 Jan 2014 @ 9:19:43 pm from IP #
Morbo
Member

do you have rising damp? Or are you afraid of condensation?
Around my house they cast concrete on top of the existing ground level, so that the house sits in a 100 or so mm deep ditch. So water wants to go there instead the other way. Plus of course the air movement is somewhat restricted. On a windy rainy day the ground underneath the house is quite wet up to 1m or so inward, takes forever to dry.

Apart from that, double glazing would be more reasonable, its already a novelty down here. Where to get triple glazing from and what will it cost?

Posted Friday 24 Jan 2014 @ 9:47:42 pm from IP #
Eamon
Member

Hi Ankerre, have you looked at -'double bubble thermal foil wraps. They have fantastic insulative values especially radiative energy. Having the double air gap greatly reduces conductive temps. This will not impact greatly on the builders worry of dimension changes in wall thicknesses. Allows for good air gap for insulation. If you do choose it or similar -it is essential you have good ventilation which "moves" as otherwise you will get trapped condensation and rot. Baring this in mind if you have the void running to the roof space, you then place a fan system drawing the air form the roof space ducted down to the lower ground space, you will then eliminate the ventilation worry, move nor roof air to the colder part of house creating thermal equalisation and in turn whole house destratification. This in turn negates the huge worry of comfort because you will have svn temps high and low throughout the year. In respect to the internal walls, high density insulation between the walls will reduce noise across the full db range, using mdf is not a good idea as the sharper sounds will travel through. MDf increase's reverberence. The dense insulation if packed tightly should absorb the resonance between the gyproc, stud ,gyproc.

If you do have damp, an additional fan to move the warmed up subfloor air out to the externals, but also negating the risk of creating positive pressure in the subfloor area- (bad idea)

Posted Friday 24 Jan 2014 @ 11:42:58 pm from IP #
Eamon
Member

Morbo said:

Also, instead digging underneath the house and by this putting it into a pond (so rainwater wants to get underneath the house) why not just lift it up? Not much to it, got mine restumped/relevelled, only takes a few bottlejacks. And you want to gut your house anyway, no need to worry about cracked plasterboard.

I like your style Morbo - this also gives great end results for old houses because it allows for straightening or rebalancing any undulations in levels that happened over time. - Yes greeter air passage whereby you can then possibly use for increased storage (depending on height), you should have no problems with heritage as you are not altering the design. If in a flood zone, you greatly reduce risk by going up, you also may be able to avail of greater veiws from the house at a new height (I don't know what you are looking at -!!!) All services can easily be adjusted, and new termite barriers put in place. Thermal slabs or panels could also be incorporated to maximise solar absorption.

Posted Friday 24 Jan 2014 @ 11:54:10 pm from IP #
Morbo
Member

I was more thinking about a few 100mm or so. Instead of scraping the dirt out from underneath, lifting it up to some degree would be way easier.

The house being on stumps, doubt there will be huge pressure differences.

Subfloor temps are slightly lower than ambient at daytime and slightly higher at night, but I doubt you could utilise that. Ad you try do get cooler air in in summer time you will soon draw the warm ambient air in.

With 500 or so mm clearance I would not store things underneath the house. Still blocks the air flow, Had to get rid of the dodgy concrete landing on the front as it caused the floor beams next to it to rot. Now its a deck and all is nice and dry. The only regret is, should have went for modwood or the like

Posted Saturday 25 Jan 2014 @ 2:40:56 am from IP #

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