Ventilating Dormer Room

Oldstyle1

We have 2 dormer rooms in our house which have windows to front of house and velux's to back.

THey are a a good size room but they can become very stuffy this time of year

I am just wondering is there anything you can put in to better ventilate these type of rooms.

Thanks

engineermike

Hi Old style,
The normal ventilation practices or fixtures can be applied in rooms built into the roof space. Just remember that the stuffyness of the rooms in summer weather usually corresponds to colder extremes in the winter months. Any ventilation should be able to be closed off when required by the occupants.
If one of the sides is a south facing aspect then its going to make the room very warm at this time of year coupled with the fact that heat from the ground floor is migrating to those rooms under the normal heat rising convection.
Having blinds on the south facing side (either the velux's or the dormer windows) will help somewhat reducing the glass house effect of the sun throughout the day.
Ventilation itself : Firstly if there is gable walls at the property install background vents at either gable end which will allow for a type of cross venting of the warm air in the rooms. installation costs are a couple of hundred quid as its the most basic ventilation type and cheapest materials that are installed in a property. It consists of an internal vent grille (open / close type- usually white), a hole being drilled in the wall approx. 4" or 105mm and a piece of soild poly pipe or 'wavin' pipe inserted and cut to end flush with the outside and inside face of the wall. Externally a 'louvre' metallic grille plate is installed. The labor is the most expensive cost - drilling through the inner and outer wall leaf, the materials are 20 /30 euro max.
If there's no gable walls on the floor with the 2 dormer rooms. The same internal vent grille type, the connecting pipe will be a more flexible type specifically for roof ventilation connections (although your going to want it kept as straight as possible when installed as bends will reduce the amount of air circulation you will achive). Externally a roof vent tile is mounted in place of a removed tile or slate.
The material cost is then pushed up for this type of install as the vent tiles cost from 50 - 100 euro each. Try and go for the universal vent tile as this can be trimmed / cut to match any or nearly any roof tile type or slate sizing. Its also the cheaper at 55 euro ( I bought 2 in Goodwins last week).

http://www.ubbink.co.uk/connect/1617/_32_1072_1617_/C/Tile_and_Slate_Vents/
The Labor also increases a bit as the builder / contractor is working on the roof.
The trick to getting some ventilation of the hot air and exchange with cool air is to know where the sun is on your property through out the day. If you can mount the vents in areas that are shaded it will help what your trying to achieve - so for instance if your out working throughout the day and the rooms are in use early evening and throughout the night then try to mount your vents on the northern aspect of the building. The air is slightly cooler there from midday / 2 pm on wards, right into the evening.
Opening one or two of the windows then should allow an exchange of air. Also mounting the wall vents in the side wall of the dormers is an option as they will be shaded at different points in the day and smaller or neater vent grilles are available (if at a higher cost than the standard ones).
The other alternative is to install a forced air system or MHRV system, but your talking serious €€€€
mf