METAL ROOFING insulation to avoid SWEATING

[Brett2021]

I am in the process of renovating an old stable block measuring 9 meters in length and 5 meters in width. The roof was previously covered with bitumen sheets, but I am now replacing it with thin, box-shaped corrugated metal sheets.

I have already made progress in replacing the side wooden cladding and have now reached the stage of planning the roofing. The stable block was originally used as a stable and workshop, but I am considering repurposing it into three separate sections:

• One-third as an office (if feasible until peak winter)
• The middle section for cycle storage
• The remaining section for log storage

Each section is already separated.

Main Concern: Preventing Condensation ("Metal Roof Sweating")​

My primary concern is how to prevent condensation from forming on the metal roofing sheets.

Planned Roofing Layers (From Outside to Inside)​

1. Metal Sheet
2. Polythene Cover or Breathable Membrane
3. Thermal Insulation (To be decided)
4. OSB-3 Board (11mm)

There will be no gaps between these layers, except for the eaves of the metal sheets, which will be sealed with foam fillers.

Choosing the Right Insulation​

I have been advised that a rigid insulation board like Celotex is the best option. However, with costs exceeding £500, I am looking for more budget-friendly alternatives, including:

1. Foil Sheet
2. Multi-Foil Insulation
3. Van Insulation Foil Foam Soundproof Underlay

At the moment, my preferred choice is van insulation foil foam soundproof underlay, as it is available for under £100. However, I am unsure whether this is the right solution.


I would greatly appreciate any expert advice or recommendations. Thank you!

 

[DAZB]

I have used the box profile insulated metal roof sheets before and they are available in a large range of thicknesses. The inside is a white metal skin and so does not need any finishing and they can do an anti condensation option. You can order them cut to length and are quick and easy to install. I have used both the box section and also the tile effect versions and have an upcoming project which I will be using them for again so I personally can recommend. Do a Google as there is loads of choice out there with thickness, style and colours etc....

 

[Brett2021]

I already bought normal box profile sheets as I explained. Now I am trying to see what low cost thermal insulations I need to have to avoid metal sheeting 'sweating' due to condensation. thanks.

 

[DAZB]

I am in the process of renovating an old stable block measuring 9 meters in length and 5 meters in width. The roof was previously covered with bitumen sheets, but I am now replacing it with thin, box-shaped corrugated metal sheets.

I have already made progress in replacing the side wooden cladding and have now reached the stage of planning the roofing. The stable block was originally used as a stable and workshop, but I am considering repurposing it into three separate sections:

• One-third as an office (if feasible until peak winter)
• The middle section for cycle storage
• The remaining section for log storage

Each section is already separated.

Main Concern: Preventing Condensation ("Metal Roof Sweating")​

My primary concern is how to prevent condensation from forming on the metal roofing sheets.

Planned Roofing Layers (From Outside to Inside)​

1. Metal Sheet
2. Polythene Cover or Breathable Membrane
3. Thermal Insulation (To be decided)
4. OSB-3 Board (11mm)

There will be no gaps between these layers, except for the eaves of the metal sheets, which will be sealed with foam fillers.

Choosing the Right Insulation​

I have been advised that a rigid insulation board like Celotex is the best option. However, with costs exceeding £500, I am looking for more budget-friendly alternatives, including:

1. Foil Sheet
2. Multi-Foil Insulation
3. Van Insulation Foil Foam Soundproof Underlay

At the moment, my preferred choice is van insulation foil foam soundproof underlay, as it is available for under £100. However, I am unsure whether this is the right solution.


I would greatly appreciate any expert advice or recommendations. Thank you!

You said you were replacing it with the box section sheets but then went on to mention you had "reached the stage of planning the roof" leading me to think you had not yet decided or bought the sheets. Your planned option is pretty similar in make up of the insulated panels but do remember you may need to consider ventilation somewhere along the line.