ᐅ Roof renovation with aluminum, is it recommended?

Created on: 15 Jun 2017 18:28
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Altbau1930
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Altbau1930
15 Jun 2017 18:28
Our energy consultant recommended an aluminum roof covering after inspecting our roof, since we plan to replace the covering anyway.

So, a new installation on the original roof frame, including insulation.

Advantages of aluminum roofing:

- very low material costs compared to traditional roofing
- available in many colors and styles
- only 10% of the weight of roofing made from slate, concrete tiles, etc. (good for older roof structures)
- there are apparently pre-fabricated panels with insulation
- very long durability, over 100 years with proper installation and maintenance

Disadvantages:

- high thermal expansion, which must be considered during installation (special allowances and fastenings are needed)
- thermal expansion can cause creaking noises
- the thin aluminum sheets are easily dented, for example by hail. Not all insurance policies cover such damage.
- the insulation should also serve as soundproofing, since otherwise raindrops may be audible inside the house
- corrosion can occur if the aluminum elements are fastened with "incompatible" metals or come into contact with them in other ways

Unfortunately, I haven’t found much information online about aluminum roofs on older houses yet, so I wanted to ask here if anyone has experience with this? We are generally leaning towards aluminum roofing when the renovation starts at the end of the year.

What do you think?
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Nordlys
18 Jun 2017 10:00
I only know this material from shipbuilding, where it is commonly used. It forms its own protective layer, so it does not need to be painted. Aluminum must never come into contact with steel, especially stainless steel. Aluminum to copper contact is particularly bad. In the presence of water, aluminum breaks down into a powdery substance. The contact surfaces need to be insulated with plastic bushings, for example. Then it works well.
Aluminum is lightweight. Whether it is actually more cost-effective than a metal sheet roof, I doubt.
Karsten
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Altbau1930
18 Jun 2017 15:04
Instead of Monday, the roofer will come to us on Thursday now. He is supposed to give me some information about the aluminum roof and the prices.

I will report back.
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SvenP
22 Jun 2017 19:33
I would say an energy consultant should stick to their area of expertise.
A roof covering with large-format sandwich panels looks visually unsuitable for a residential building and is also very difficult to install properly on an old, uneven roof frame. A covering with small-format aluminum shingles or standing seam aluminum sheets is by far more expensive than a tile roof.

What does the old roof structure look like, and what are the goals (energy saving ordinance renovation or KFW [Kreditanstalt für Wiederaufbau])?

Regards, Sven
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Altbau1930
22 Jun 2017 20:44
So far, the energy consultant has only mentioned KfW. Today, he was on site together with the roofer who will carry out the work later, and we discussed both roofs. I need to correct the measurements: each roof area is approximately 120 sqm (1300 sq ft), so the total is roughly 240 sqm (2600 sq ft).

I also visited an older building nearby that was recently renovated with dark aluminum shingles. It looks very good even from a close distance. Only the dormers and chimney claddings are covered with slate, which visually blends well. We are now being offered the same solution, including the removal of the last section of the chimney in the attic and on the roof. This will be replaced by two insulated stainless steel pipes, which are used for external chimneys.

I am very curious to see the full offer. It includes:

- Scaffolding costs
- Removing roofing from both roofs down to the beams and rafters, which can remain in place. One roof has a slate covering, the other has a bitumen membrane
- One roof of 120 sqm (1300 sq ft) with KfW-compliant external insulation and aluminum
- One roof of 120 sqm (1300 sq ft) with only minimal insulation (extension, upper floor already insulated) and the same aluminum cladding
- New gutters
- Removal of one dormer
- Two larger Velux windows that comply with KfW standards
- Cladding one existing dormer with slate

Before or after, both timber frameworks will be treated against possible woodworm infestation by a pest control specialist.