Insulation and ceiling options for verandah

[Bells67]

Hi there, loving this workshop forum! 

Like others, I've been reading through a bunch of posts to see if there were already answers to my questions but couldn't find anything that covered the lot so I've started this new post. Hope that is okay!  We are 5 years into a 1-year renovation plan and one component has been replacing joists, deck boards and handrails on our verandah and adding insulation and a ceiling to stop condensation (which is prolific) and make it cooler in summer.  We are not quite done with the decking, but getting close.  Because we have painted posts, beams and rafters which will require re-painting, we need to decide on the insulation and ceiling options to use so we know which beams/rafters will remain visible.    

We have a three-sided wrap round deck with bullnose roofing (each side is 4m long and it's 17m long on the front). From exterior house wall to outside deck facia beam, it's around 2.0m long.  There is absolutely nothing consistent about the spacing between the rafters - or anything else about our house for that matter - so sadly, it's not a matter of simply buying 900mm wide insulation panels and slipping them in between each. Spaces between rafters range from 780 to 880 (I think, haven't measured them all). Power runs along one of the rafters and is then channeled on top of the facia beam (under the roof) to 3 or 4 flood lights that are also attached to same along the length. The corners, where the hip rafter is, might make installing insulation and a ceiling complicated?  Photos are attached. I was thinking that the simplest ceiling option is installing insulation close under the roofing somehow, then slipping the ceiling panels in above the facia beam (where it would sit above) and screwing the panel into the bottom of the battens. This would leave most of the rafters exposed, but not the battens.  

My questions:

- Is there a good insulation option (like foil board or Aircell or some other product that is waterproof) that can be easily cut to size and installed directly under the colourbond within each rafter space? 

- If so, how would we attach it if we are not removing the bullnose to sit it on top of the rafters? Can it sit on the ceiling panels, or does it have to be close under the bullnose? We get heavy condensation, so it needs to be rot/water/mould proof or effective enough to stop the condensation.

- What would be most cost effective, easy to fit, mould-resistent ceiling panel options?  Hardie-board?

- Is it okay to fit them into the rafter spaces as I've noted above, or should we simply install ceiling panels in large sheets on the lowest points (bottom of rafters) with all the joins running paralell with the deckboards? 

If you think this belongs on a different 'board' or I need to seek help elsewhere, it's totally okay to let me know. I have some other questions relating to installation of french doors where our bay windows used to be and I'll place that on the 'Whole of House' board.

Thanks, MichelleCorner with hip rafterAlong front length of deckpower and lights to work aroundAnother along the front

[Bells67]

Thanks so much @Jewelleryrescue 

The groovey pics are excellent and I see what you mean now.  We were thinking of running it the other way (paralell with the house) as the width of the rolls fit almost perfectly between the first and middle rafters but I expect what you have shown here (house to facia beam) is the better option. 

Very helpful and I really appreciate it!  It may be a little ways down the track, but I will report back to let everyone know our chosen solution and the results. 

[Bells67]

Hhi @MitchellMc 

Thanks heaps for your words of wisdom - definitely helped me understand better how condensation forms.  I also didn't know Gyprock made a water-resistent version, so I'll look at that for sure.

Cheers

Michelle

[Bells67]

Afternoon @Dave-1 

Yeah, old houses, how much fun are they!?!

We love the bullnose look, so would find that hard to part with - so probably not an option to replace with straight colourbond. The hesitation with taking off the existing sheets really only to do with how awkward it is get up there (a fair way off the ground) and neither of us are super-nimble anymore  

As the green comes off on our shoes when walking on it, we would really like to replace all of our roof but the quotes proved that it was absolutely out of the budget for us at the moment. Couple of costly components - removing and reinstalling solar ; the additional cost of bullnose compared to normal colourbond and adding sarking which we would absolutely need to do. Ho hum.  

There are some fantastic ideas here, including yours, and I will be sure to post back once we have made a call and installed the chosen solution. This will be a little way down the track - but hopefully our results will still helpful to others. 

Thanks to everyone for the input, what an excellent group! 

Michelle

[Jewelleryrescue]

Hi @Bells67 

I hear you re  running the rolls length ways maybe you can do some  sort of test run using simple  kitchen alfoil from the top rafter to the bottom just tape it up and see if any condensation dripping at the middle for a couple of meters if you wish proof of  a concept.

Dripping condensation mid  rafter is what  i dont want  for you.

Alfoil is good but  thremal break will be 20x  better than alfoil alone.  If you like  the alfoil  test. as  success.