Fitting and the whole job
Tu Ventana (legal guarantee of conformity)
Spanish consumer law gives you a 3-year guarantee of conformity on the goods and their installation (art. 120 TRLGDCU). This is the guarantee that covers our work.
Terrace enclosures
Terrace enclosures that stay dry in an autumn storm
Tu Ventana Costa Blanca encloses terraces and balconies with insulated Kömmerling uPVC frames and double glazing, from Alicante to Denia. Often the job is not a new enclosure: it is rebuilding an old one that lets water in every autumn.
We speak English. Eduardo answers on WhatsApp, 9:00–20:00 Spain time (8:00–19:00 UK time), and replies within 24 hours.
The problem
Water rarely comes through the glass. It comes in at the bottom.
Much of this coast was built in the tourist boom of the 1960s and 1970s. Most flats had a projecting terrace, and most of those terraces were later enclosed. The enclosures were usually light frames resting on the balustrade, with no subframe, no window sill and silicone as the only seal.
They survive because rain is scarce, about 300 mm a year. The trouble is how it falls. A few autumn storms can drop over 100 mm in hours, pushed against the façade by an easterly wind.
That water gets in where the frame meets the parapet wall, through the bottom rail and at the side joints. So when we look at a leaking terrace, we check the subframe, the drip sill and the drainage first. Sometimes only the joint needs rebuilding; sometimes nothing is worth saving, and we say so.
What we fit
For a terrace enclosure in Benidorm or along the Costa Blanca, Tu Ventana Costa Blanca fits insulated Kömmerling uPVC frames with double glazing and triple-barrier sealing. The main opening is usually a PremiDoor76 lift and slide door, with fixed panes elsewhere. English-speaking owners get an answer on WhatsApp within 24 hours.
This is the same product as a good window, applied to the whole front. The frames have insulating chambers and steel reinforcement. The seal to the wall is built in three layers: watertight outside, insulated in the middle, vapour-tight inside.
Lift and slide on the main opening. The PremiDoor76 lifts its sash to slide, then presses it onto the seals to close. It reaches air-permeability class 4, while an ordinary sliding door rarely passes class 2. On high, exposed floors, it is what we recommend.
Fixed panes on the rest of the front. A fixed pane is the cheapest and most watertight part of an enclosure, because it has no hardware to fail. Combining one lift and slide section with fixed panes usually costs less for the same result.
Ordinary uPVC sliding doors are reasonable up to about 2.5 m on sheltered terraces. Their limit is the brush seal: in a strong easterly wind with driving rain, air and water can get past it.
The glass: solar control is the central decision
In an enclosure, glass covers more area than anywhere else in the home. The key figure is the g-value, the share of solar energy that gets through.
- Solar control glass on south and west fronts. Ordinary glass lets through about 80 % of solar energy; solar control glass can stay below 40 %. See the solar control glass guide.
- Low-E double glazing with argon as the base everywhere.
- Acoustic laminated glass if the terrace faces bars, nightlife or a promenade.
- Laminated safety glass where panes reach the floor.
We rarely recommend triple glazing here. It is designed for hard winters, and on large sliding sashes its weight adds cost to the hardware for no return.
Frameless glass curtains or an insulated enclosure?
Frameless glass curtains and insulated uPVC enclosures do different jobs. Glass curtains are single panes that slide and fold to one side. Tu Ventana Costa Blanca does not sell them. On the Costa Blanca, including Calpe, it fits insulated Kömmerling uPVC enclosures with double glazing for English-speaking owners, for terraces used all year. Kömmerling guarantees the profile for 10 years.
Glass curtains have their place. For a porch, or a terrace used in spring and autumn, they stop wind and rain and cost noticeably less. What they are not is a façade. They have no thermal break and no insulating glass unit, and they are not designed to separate an air-conditioned room from the street.
The honest question is what you will do in the space. If it is for drying clothes, storing bikes and eating outside in spring, glass curtains may be enough. If the sofa is moving out there, it needs an insulated enclosure, or the first August will disappoint.
| Frameless glass curtains | Insulated uPVC enclosure | |
|---|---|---|
| What it is | Single panes that slide and fold to one side | Kömmerling uPVC frames with double glazing |
| Thermal break and insulating glass unit | No | Yes |
| Separates an air-conditioned room from outside | Not designed for it | Yes |
| Suits | A porch, or a terrace used in spring and autumn | A terrace used all year, or joined to the living room |
| Relative cost | Noticeably lower | Higher |
| Does Tu Ventana Costa Blanca fit it? | No | Yes |
Joining the terrace to the living room: the heat trap
The most expensive mistake is not water. It is turning the terrace into part of the living room by changing only the frames.
A terrace is the most exposed part of the home: a floor over open air, a ceiling that is the neighbour’s slab, three sides outside. Enclose it without dealing with floor, ceiling and orientation, and you have added a greenhouse to your lounge.
Plan it before fitting. Use solar control glass on south and west fronts, and an outside shutter or awning. Insulate the floor and ceiling if the terrace joins the room. If none of that will be done, keep a sliding door between them and use the terrace as an in-between space.
Drainage and slope: where enclosures fail
A terrace is built to get wet: it slopes outwards to a drain. Once enclosed, that drain is inside. It must stay accessible and clear, or water will pool against the bottom frame.
Sliding tracks have drainage holes. Near the beach, sand blocks them sooner than anyone expects. Checking them once a year, before the autumn storms, prevents most "water is coming in" calls.
The top joint against the slab above also needs a seal that absorbs the slab’s movement in the sun. Silicone alone does not, which is why old enclosures leak without anyone touching them.
Permissions: check before you commit
Enclosing a terrace changes the façade, which is usually a common element of the building. Community approval may be needed, and many buildings already have an approved model for colour, frame type and layout. Check with your community of owners or the community administrator first.
Municipal rules may also apply, and they vary between towns. Check with the town hall, or with an architect, before signing anything. An enclosure can also affect how the floor area is counted; that question is for an architect, not a fitter.
Tu Ventana Costa Blanca encloses terraces in Benidorm and across the Costa Blanca for English-speaking owners, but it does not grant permits or give legal advice. Your community of owners may need to approve the enclosure, and town hall rules vary. Eduardo can tell you in English on WhatsApp what to ask your community administrator.
When you do not need the expensive option
A small utility terrace is often better left open. Enclosing the three or four square metres by the kitchen, with the washing machine and drying rack, rarely works. Clothes dry without ventilation, and with 65–70 % humidity from the sea that ends as mould on the wall. The space overheats in August and gains no useful room.
If that terrace leaks or its frames are finished, replacing the frames and sorting the ventilation costs less and works better.
A full lift and slide front is rarely needed. One lift and slide section on the main opening, with fixed panes elsewhere, usually does the job for less.
Triple glazing does not pay here, and the 88plus Passivhaus system has no place in a terrace enclosure on this coast.
How the price is worked out
An enclosure is priced by the linear metres of terrace front and the type of opening in each section, not by the number of windows. The main cost drivers are:
- The length and height of the front, measured on site.
- The mix of sections: lift and slide, ordinary sliding or fixed panes. Fixed panes bring the cost per metre down.
- The glass: solar control, acoustic or laminated safety glass.
- The state of the parapet wall, subframe and drainage, and whether the joint must be rebuilt.
- The finish, and any colour set by your community’s approved model.
- Access, floor height and removal of an old enclosure.
Tu Ventana Costa Blanca makes and fits terrace and balcony enclosures in Alicante and across the Costa Blanca. After a site survey, English-speaking owners receive a fixed written price with VAT included, and the fitting carries the 3-year legal guarantee. The quote also states the VAT rate applied.
How the job works
- 1
Tell us about the terrace
Tell us the orientation and rough size in the quote form. Eduardo replies on WhatsApp, where you can send him a few photos (9:00–20:00 Spain time, 8:00–19:00 UK time).
- 2
In-person site survey
We look at the parapet, drainage and slab before the glass. If you are away, a key holder lets us in.
- 3
Written, fixed quote
The quote lists each section, the system, the glass, the hardware and the VAT. Check community and town hall rules before you sign.
- 4
Fitting
The frames are made to measure and fitted on a subframe with triple-barrier sealing. An old enclosure is removed first.
Our work
What a well-finished installation looks like
Jobs by our Madrid team, the same company as our Costa Blanca office: Kömmerling uPVC windows, doors and enclosures fitted by our own people.
Glazed galleryGlass roof on uPVC profiles Indoor poolEnclosure exposed to humidity and chlorine 
House with a gable windowThe apex glazed without a frame splitting the glass
Who signs what
Four guarantees, and who gives each one
The fitting is covered by the 3-year legal guarantee of conformity. Kömmerling guarantees the profile for 10 years; glass and hardware follow their manufacturers.
Profile
Kömmerling
Signed by Kömmerling, not by us.
Glass unit
Glass manufacturer
Signed by the glass manufacturer, not by us.
Hardware
Hardware manufacturer
Signed by the hardware manufacturer, not by us.
Tell us about your terrace
Where it is, which way it faces, how long the front is, and whether it leaks today.
Questions we are asked
Frequently asked questions
Do I need permission to enclose my terrace in Spain?
Possibly, on two levels. The façade is usually a common element, so your community of owners may need to approve it or may already have an approved model. Municipal rules may also apply and vary by town. Check both before signing anything.
How much does it cost to enclose a balcony?
Each front is different, so there is no single figure. An enclosure is priced by linear metres of front and the type of opening in each section. Fixed panes cost less per metre than sliding sections. After a site survey you get a written, fixed price with VAT included.
Glass curtains or uPVC frames: which is better?
It depends on use. Frameless glass curtains stop wind and rain and cost less, but they do not insulate. For a room you will heat or cool, you need insulated frames with double glazing. We fit insulated Kömmerling uPVC enclosures; we do not sell glass curtains.
My enclosed terrace leaks in autumn storms. Must it all be replaced?
Not always. Water usually gets in at the joint with the parapet wall, through the bottom rail or through blocked track drains, not through the glass. Often rebuilding that joint, adding a drip sill and clearing the drains is enough. We look before we propose anything.
Will an enclosed terrace get too hot in summer?
It can, if nothing else changes. Use solar control glass on south and west fronts, add outside shading, and insulate floor and ceiling if the terrace joins the living room. Otherwise keep a door between them.
Can you do the work while I am in the UK?
Yes. A key holder lets us in for the survey and the fitting, and you deal with Eduardo in English on WhatsApp. See replacing windows from abroad.
Does enclosing a terrace add floor area to my property?
It can affect how floor area is counted. That is a question for an architect and the town hall, not for a window fitter. If your case needs it, get that advice before work starts.