The answer
The disadvantages of VELUX windows are summer heat through the glass, rain drumming on a pane close to your head, condensation in humid rooms and the effort of reaching a window set high in a slope. Each has an answer in the glazing, the size, the blind or the way the window opens, and we choose those to suit the room.
Summer heat
A roof window faces the sky, and on a bright afternoon the sun comes straight through it. A loft room under a roof with a south-facing window can warm up faster than a room with a wall window, because the sloping glass faces the high summer sun more squarely and the heat collects under the slope.
Three things bring it down. The first is the glazing: coated solar-control glass turns back part of the sun's heat. The second is a blind. A blind fitted outside the window stops the heat before it reaches the glass, and one fitted inside softens what arrives. The third is the size of the window, because a smaller code lets in less sun. The direction the roof faces matters too, and a north-facing slope gives gentler light than a south-facing one.
An opening window helps in the evening, as warm air rises and leaves through the top of an open sash, a point taken further in whether rooflights make rooms too hot. A loft bedroom is where the heat is felt most, so that is the room where we look hardest at the glazing and the blind together.
Rain noise
Rain on glass is louder than rain on slate, and in a loft bedroom the pane is only a short distance above your head. A heavy shower can be heard clearly inside, and some people find it soothing while others find it keeps them awake.
The glazing makes the biggest difference. Some glass specifications are built to reduce the noise that rain makes, for instance with a laminated pane that dampens the sound. Triple glazing also adds a layer between the weather and the room. A smaller window carries less area for rain to strike, so a modest code over a bedroom bed keeps the sound down further.
If the room is a bedroom and you are sensitive to noise, say so when we survey, and we will choose the glazing with that in mind. It is easier to settle before the window goes in than afterwards.
Condensation
Moisture in the air settles on the coldest surface in a room, and a window can be that surface. Bathrooms and kitchens put a great deal of steam into the air, and a bedroom takes on moisture overnight. A roof window in one of those rooms can show a film of moisture on the inside of the glass on a cold morning.
This surface condensation is a ventilation matter, and it clears when the room is aired. An opening sash helps, and so do an extractor fan and a habit of leaving a bathroom door open to the landing after a shower. Better glazing helps too: a warm-edge spacer keeps the edge of the inner pane warmer, so there is less cold glass for the moisture to settle on, and the causes are set out in rooflight condensation.
Condensation between the two panes is a different matter. The seal around the rim of the double-glazed unit has let go, and the film forms in the gap between the two panes, where no cloth can reach. A new glazed unit or a new window is the way out, and replacing is our work.
Reach, cleaning and opening
A window set high in a slope can be awkward to open and clean. The handle on a centre-pivot window sits at the top, and a pole may be needed to reach it from a landing. Cleaning the outside depends on the roof pitch and how far up the slope the glass sits, and some windows are fitted with a design that lets the sash be turned so the outer pane can be cleaned from inside.
Position and opening type are the answers here. A window set a little lower in the slope is easier to reach, and a top-hung window gives clear headroom at the opening, where you can look out of it. Where the ceiling is high or the window is above a staircase, an electric model opens by a switch or a remote, and where the model has a rain sensor it shuts the sash when drops fall.
Blinds add to the reach question. A blind on a high window is worked with a pole or a remote, so it is worth deciding at the start whether you want the blind to be manual or electric. The code also matters. A tall window reaches farther up the slope, so the choice of height changes how easy the top edge is to reach. Choosing the size from the code shows how that choice is made.
A leak at the flashing, and how it is avoided
The other drawback people name is a leak. A roof window is a break in the weathering, and water can find its way in if the flashing does not suit the covering or has been fitted badly. The remedy is the right kit for the roof, fitted with the underlay dressed around the frame. How a kit is chosen for each covering is the subject of flashings for slate, stone slate and tile.
Our workmanship on every window we install is guaranteed for ten years, and our guarantee page describes what it covers. To talk one of these points through for a particular room, send a WhatsApp message to 07880 284133.