- You want to insulate your attic at € 1?
- Made to measure (our building site)
- Laying a business model
- Flat hood or dome
- To take into account: the "FLU" reference system
- 1 Drilling hoppers
- 2 Masonry of the bases
- 3 Implementation of the waterproofing
- 4 Glazing
The skylight is a relatively inexpensive way to bring natural light into a windowless room. Provided it is under a flat roof or very low slope: that of an extension or a garage, for example.
Cost: from 250 € (without installation, for a fixed skylight on steel curbs)
Time: 4 days to two
Equipment: meter, ruler, level, mallet, trowel, shovel, trough, bolt cutters or hacksaw, cartridge gun, chisel hammer, hammer chisel, impact drill, blow torch...
The project consists here of illuminating the ceiling with a long piece by means of three rectangular skylights. Their dimensions (120 x 60 cm) and locations are studied in order to optimize the brightness. The hardest part of the job is to drill the hoppers into the existing terrace, consisting of a concrete slab on brick slabs. The thickness to be excavated is about 25 cm. The installation of skylights does not present any particular difficulty, the important thing being to well seal the chassis forming support (see diagrams).
You want to insulate your attic at € 1?
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Made to measure (our building site)
Custom cut, safety glass is available in various thicknesses of 3 mm (approx 42 € / m2) at 19 mm (about 215 € / m)2).
Laying a business model
Manufacturers provide you with tools to calculate the right lighting surface for your needs.
Flat hood or dome
Skylights are made here from scratch. Mounted on a brick base, they consist of an aluminum frame covered with a thick glass of safety glass (19 mm). To simplify life, it is possible to opt for a model that is found in commerce (Velux, Glazing Vision, Hexadome, Skydôme...). They can be opened or fixed, with insulated galvanized steel, reinforced polyester or PVC curb. These joineries are provided, according to the versions, of a flat hood or a dome (curved, pyramidal...) in cellular polycarbonate or in safety glass.
High end furnishingsThe roof terrace is arranged and covered with composite strips that "marry" the three skylights. Equipped with a garden furniture, the place is transformed into an open-air relaxation area. There are several types of skylights (round or square). Manufacturers specify their installation conditions: on sealed roofs (bitumen - our example, PVC membrane, cold liquid...) or dry (steel tanks, aluminum, fi brocement...). In the case of a dry roof, molded bases are provided to adapt the installation to the profile of the roofing materials.
To take into account: the "FLU" reference system
Attention should be paid to the energetic performance of the proposed skylights. The comparison tool is the "FLU" reference, which takes into account three parameters: the solar factor (amount of energy passing through the glazing), the luminous efficiency and the heat transfer coefficient U.
For each, the ranking is based on a scale of A (best index) to E (lowest index). When purchasing a skylight, make sure that the model is able to prevent, or at least delay, intrusion attempts.
1 Drilling hoppers
The perimeter of the openings is plotted in the format of the glass plates, minus the thickness of the solid brick base.
To prime the hole, use a precise and handy tool, of the perfo-chisel type.
Continue digging with a hammer or concrete breaker (rental).
The reinforcing mesh of the slab is cut as and when using a bolt cutter or a hacksaw.
To maximize light penetration, trim the edges of the hopper by flaring them a little inward.
Clean and dust carefully the sides of the hole and the surface of the terrace.
After having moistened them, equalize the edges with the cement mortar applied with the trowel, then floated.
2 Masonry of the bases
Wait 24 hours to mount the curb in full bricks.
The laying is done on edge, flush with the hoppers, with the same type of mortar.
The interior of the hoppers is insulated with 20 mm of expanded polystyrene and a 10 mm thick plasterboard fixed by adhesive mortar pads.
Cement mortarAvailable in powder (which hardens on contact with water), the cement mortar becomes strong and resistant when drying.
Before installing the base, it is recommended to moisten the bricks and drain them to promote the grip of the mortar.
3 Implementation of the waterproofing
The masonry bases require a tight seal.
Cut strips of felt felt for this purpose. Calculate their width so as to overflow clearly on the terrace.
The curb is reinforced by aluminum pegs anchored and screwed, then the whole receives an asphalt base.
To prepare the gluing of the sealing strips, the product is softened with the torch.
Lay strips quickly and heat them upside down to improve bonding.
It is important to smooth them on the sides and top, using a wooden block for example.
Additional protection is provided by the application of a waterproof coating.
Generously spread the bituminous coating with a trowel to improve the tightness in the corners (joints with miter cut),
Separate the glazing from the base with compressible strips, which absorb the vibrations
The compressible strips are first laid blank, cut to length and mitered at the corners.
Fasten the strips with a strong, solvent-free, polymer-based adhesive sealant.
Totally transparent, the sealant also serves to glue the glazing on the rubber bands.
Three people are needed to safely handle the heavy plate, which approaches 40 kg.
Finally, place a bead of elastomeric bitumen at the junction between the glass plate and the base, all the way around.
This sealant strengthens bonding and sealing.
Once applied, smooth the elastomeric bitumen trowel without overflowing on the top of the glazing.
Let it dry for about 24 hours.
• Predosed mortar
• Full bricks
• Liquid bitumen
• Asphalt felt
• Compression bands
• Putty adhesive in cartridge
(Axon MS 3000, Rubson MS3...)
• Elastomeric bitumen mastic
• Safety glass, thick. 19 mm