- Type of opening of a roof window
- A custom trimming
- Custom zinc fittings...
- 1 SETTING UP THE DORMANT
- 2 PREPARATION AND FIXING OF ZINC BINS
- 3 TREATMENT OF CONNECTIONS
- 4 FINISHING AND LAYING CAPOTAGES
Installing a window on a zinc roof requires mastering the folding and brazing of the metal. Indeed, the roof must be connected directly to the frame to ensure tightness.
Cost: from € 1,160 (motorized window Velux GGL UK04 of 134 x 98 cm + electric shutter UK04)
Time: 1 to 2 days
Equipment: meter, bubble level, chalk line, handsaw, screwdriver, pliers, hammer, zinc-plating tools, scaffolding...
Type of opening of a roof window
A roof window can open by rotation or projection outward. The choice of one or the other version depends primarily on the height at which the window is located...
If the top of the opening is less than 2 m from the ground, the opening by projection avoids bumping the head against the top of the opening, which always pivots inwards. On the other hand, when the top of the window reaches more than 2 m from the ground, the system by rotation is more indicated: it does not force to push on the low crossbar, which could be out of reach. The opening rotating are also the only compatible with a motorization, convenient when the window is very high.
A custom trimming
In renovation, the addition of a roof window makes it necessary to take into account the distance between the rafters and the purlins. Otherwise, when opting for a window wider than the center distance of the rafters, the frame must be slightly modified. It is necessary to integrate a hopper into which the roof window fits. This hopper generally uses one of the purlins as high or low crossbar and one of the rafters as side jamb. The two missing sides are reported. Determined according to the external dimensions of the frame, the dimensions of the hopper must be increased by a few centimeters: thus for a window of 134 x 98 cm, the increases (specified in the installation instructions) are 45 mm in height and of 40 to 60 mm in width.
Custom zinc fittings...
Outside, when the fittings are not prefabricated (to be ordered with the carpentry), the connections are made to measure with the roofing material, in this case zinc, which is particularly suitable for shaping. But a certain know-how is essential to execute the welds, with a roofing torch soldering iron. All the art is to melt tin solder on the iron tip and then apply it to the zinc. This operation requires the prior etching of the zinc with the acid and, from time to time, cleaning of the iron tip with the file.
1 SETTING UP THE DORMANT
The installation of a roof window is usually done from the inside. Here, roofing work imposes the presence of a scaffolding adding to the complexity of the site.
Before presenting the window, carefully check the dimensions of the header... Especially if you plan to install the assembly without having dismantled the opening.
Center the frame in the hopper. Screw its fastening tabs, first at the bottom left, then at the top right.
If the door has been removed, replace it. Engage its pivots and close it. From the inside, control the game around the opening. If you need to correct the squareness, pry with a pliers.
With the squareness of the frame finished, check the horizontality of the lower rail with a spirit level.
Then screw the other fixing brackets making sure that the frame is stable.
2 PREPARATION AND FIXING OF ZINC BINS
After validating the length of the tray, cut a series of retaining tabs in zinc scraps. Etch them with a soldering iron.
The gutter resting here on the rampant (and not on the hooks), the bins come to cover the edge of the gutter.
It is therefore on the edge of the channel that are welded retaining tabs (two per tray) after etching with acid.
With a shear, cut out a zinc tray making sure to make flaps at 90° to the right of the frame of the window.
Attach the bin to the next one by pressing down on the retaining tab. Block it permanently by folding this leg in the manner of a slate hook.
With a pliers, fold the flap of the side edge of the tray up under the edge of the previous tray. The two edges will be folded back on themselves (downwards) and along their entire length.
The bins are also fixed on the decking by sliding stainless steel legs. Screwed every 30 cm against the left edge of each tank, they prevent the wind from lifting them.
Then do the same for the following bins: fold the side fold, bend the top edge over the entire width of the tray, block the tray with the low retaining tab and sliding tabs...
Flatten the top of the sides carefully with a small wooden wedge.
3 TREATMENT OF CONNECTIONS
Introduce the lower bib to make sure it is fully flattened.
If this is not the case, correct the top of the bins by tapping with a zinc wiper.
In the corners, the seal is made with an L-shaped insert. Slide behind the side flap and under the lower flap.
Acid etch surfaces that will receive solder along the joints. Heat zinc and solder and perform spot welding.
After completing the lower corners, plate the top of the bins one last time. This is to eliminate the distortions that may have gone unnoticed until now.
Three prefabricated slides ensure tightness at the top of the bins under the window. Brush them on each side of each fold.
Then shorten the three slides and fold them down.
4 FINISHING AND LAYING CAPOTAGES
Introduce the bottom bib and make sure it fits the frame properly along its entire length, as well as its synthetic tips.
Then screw the bib into the sleeper crossbeam.
Screw the side covers then the hood on the frame. The following trays will start above the window. Their lower edges will be folded under the upper edges of the previous bins.