benediktr
2020-04-05 16:53:45
- #1
I have another request regarding the roof. We want to award the contract promptly and there are differences in the execution variants from 3 providers. The following structure is always the same, from bottom to top:
Steuerberater-Decke: 200 mm
PUR-WLG 023: 160 mm (possibly 2 x 80 mm laid crosswise)
Sparren 8/20 KVH C-24
(Gable walls are masonry)
The roof space is therefore constructed as a cold roof and ventilated via perforated sheets.
The following variants are offered by 3 roofers with double standing seam technology in titanium zinc or aluminum from the rafters upwards:
Variant 1:
Underlay membrane
Counter battens
Cover battens
Roof sheathing made of softwood 24 mm
Structured separating layer (Delta Trela)
Sheet metal covering
Variant 2:
Underlay membrane
Counter battens
Cover battens
Roof sheathing made of softwood 24 mm
Random mat (Rheinzink)
Sheet metal covering
Variant 3:
Roof sheathing made of softwood 24 mm
Diffusion-open Tyvek membrane with laminated grid channels
Sheet metal covering
In variant 3, the underlay membrane and battens are omitted and the sheathing is attached directly to the rafters. However, this is still the most expensive offer because the price per square meter for the sheet metal is excessive.
Now my question is, who is correct here? Can the underlay membrane be omitted? What do you think of the roof constructions? Especially the insulation, which is installed by oneself.
In general, in my opinion, the roof is always ventilated through the structured separating layer with the dimples?
Steuerberater-Decke: 200 mm
PUR-WLG 023: 160 mm (possibly 2 x 80 mm laid crosswise)
Sparren 8/20 KVH C-24
(Gable walls are masonry)
The roof space is therefore constructed as a cold roof and ventilated via perforated sheets.
The following variants are offered by 3 roofers with double standing seam technology in titanium zinc or aluminum from the rafters upwards:
Variant 1:
Underlay membrane
Counter battens
Cover battens
Roof sheathing made of softwood 24 mm
Structured separating layer (Delta Trela)
Sheet metal covering
Variant 2:
Underlay membrane
Counter battens
Cover battens
Roof sheathing made of softwood 24 mm
Random mat (Rheinzink)
Sheet metal covering
Variant 3:
Roof sheathing made of softwood 24 mm
Diffusion-open Tyvek membrane with laminated grid channels
Sheet metal covering
In variant 3, the underlay membrane and battens are omitted and the sheathing is attached directly to the rafters. However, this is still the most expensive offer because the price per square meter for the sheet metal is excessive.
Now my question is, who is correct here? Can the underlay membrane be omitted? What do you think of the roof constructions? Especially the insulation, which is installed by oneself.
In general, in my opinion, the roof is always ventilated through the structured separating layer with the dimples?