What overhang depth blocks the summer sun?
For a south facade, a porch with its edge at 3 m blocks the June sun with 1 m of overhang and the September sun with 2.5 m. But to live under it you need 3–3.5 m of depth: a table for eight and room to move. That depth shades the wall until almost October.
The sums for Barcelona are simple. Midday sun height is about 72° in June, 49° at the equinox and 25° in December. The shadow projection equals the height of the edge divided by the tangent of the angle: with 3 m that is 1 m in summer, 2.6 m in autumn and 6.4 m in winter.
How does the winter sun reach the house if the porch is deep?
With 3 m of depth and the edge at 3 m, the December sun hits the wall about 1.6 m above the floor. The lower half of the glazing gets warmth and light and the upper half stays in shade. For a living room behind the glass that is usually enough, and the house stays bright.
If the overhang is deeper than 4 m, you give up some winter light indoors. Then a translucent strip of roof, adjustable louvres or a higher edge are used: at 3.5 m more winter light gets in. On a timber pergola the louvres close in summer and open in winter, and that is the most flexible option.
On east and west sides the sun is low and a horizontal overhang does not stop it. Vertical screens, shutters, fabric or a vine help there. We covered orientation and shading of the house in the orientation article.
How do you make one floor inside and out?
You need one material, or two matched in colour and texture, and a level difference of no more than 1–2 cm with hidden water drainage. The finished floor inside is raised 3–5 cm above the porch finish, and the porch is sloped 1–1.5% away from the house so that water does not run in.
At the threshold a linear drain with a 10–15 mm slot is fitted; it hides in the joint and takes any water that reaches the door. Waterproofing upstands are taken above floor level: that is what separates a dry threshold from a wet one.
Material. Porcelain stoneware 20 mm thick outside and 10 mm inside looks identical and outdoors stands up to load and frost. A stone with a rough texture goes outside and is polished inside. Slip resistance outdoors is stricter: class 3 for wet zones, with an anti-slip texture. On choosing the floor for the rooms themselves, see the flooring article.
Which sliding walls to choose, and how heavy are they?
The choice is between lift-and-slide systems and doors that retract into a pocket inside the wall. A lift-and-slide unit takes panels up to 3–4 m wide and 3 m high, with a slim profile and good sealing; a single leaf can weigh over 400 kg, so the beam and the floor under the track are calculated in advance.
Pocket doors disappear completely into the wall and the opening clears to its full width. For that the wall needs a pocket deeper than the leaf, and it cannot carry services.
What is checked. The bottom track is recessed flush with the floor, or there will be a step. Drainage is needed beside it. In Catalonia the glass is specified with solar control and triple glazing: a good terrace is designed with a margin against overheating. At the head, light motorisation: a heavy leaf is not moved by hand every day. Frames are coordinated with the look of the facade, which we cover separately.
Does a covered porch count towards built area?
It depends on the municipal plan, and there is no general answer. In most plans a porch open on one or two sides counts partially, often as 50% of its area, while one enclosed on three or more sides counts as normal floor area. Sliding glazing turns it into an enclosed space and changes the calculation.
This affects three things: the plot's occupancy limit, distances to boundaries and taxes. If the house is already at its area limit, a covered porch sometimes cannot be added without cutting something else.
So the order is: find out the ratio and counting rules for your zone from the ayuntamiento, include the porch in the design and put it in the licence. A porch glazed in later without a licence becomes an unlawful extension, which causes trouble at sale: you need an area certificate and the Catastro must match reality.
Does a porch need heating, and what are the alternatives?
On the coast heating is needed from December to February in the evenings, and a local source is usually enough. The best electric option is infrared heaters of 1.5–3 kW on the ceiling or wall, which warm people rather than air and so do not lose heat to wind. Gas patio heaters work outdoors but are noisy, smell and need gas piping.
In summer the question is cooling. Ceiling fans rated for outdoors give relief at +30 °C without air conditioning. In heat spells louvres, fabric and plants help: shade lowers the temperature under the porch by several degrees.
Services are provided before finishing: power for heaters, fan, lighting and IP65-protected sockets. Terrace lighting is kept warm and low, with two or three seating zones so that in the evening not everyone crowds into one spot.
Where to start the porch design
With three questions: which way the porch faces, how much area can and should be built, and what it looks onto, the garden, the pool or the view. Then the permit is confirmed, and then the floor material, glazing and services are chosen. The size is fitted to scenarios: dinner for eight, a sofa and a fireplace, a children's zone.
BCN YARD builds houses turnkey, and the porch is designed with the living room rather than after it: levels, drainage, electrics, glazing. We run the site in Russian and Spanish, with our own crew and trusted subcontractors, and one person is responsible for everything. The price comes in the estimate after a visit and measurements, with payment under contract in stages.
Frequently asked questions
Can glass walls be added to a covered porch later?
You can, but planning it from the start is cheaper and cleaner. It takes a track in the floor, drainage, a beam calculation and confirming the area with the ayuntamiento. Glazing turns the porch into an enclosed space and changes how area is counted, so it is added only under a licence.
Which roof is better for a porch: solid or louvred?
A solid insulated roof gives shade, rain protection and quiet, but is darker in winter. Adjustable louvres let light in during winter and close in summer, though without sealing they will not stop heavy rain. On a villa the two are often combined: a solid part by the house and louvres towards the garden.
How do you protect porch furniture from sun and rain?
Choose outdoor-grade furniture: teak, powder-coated aluminium, UV-resistant fabrics. Cushions are stored in a cabinet built into the porch wall or in a bench with a chest. A good porch is designed with storage from the outset, otherwise the cushions end up indoors anyway.