God is in the details, and one of the important details in a house’s design specially in a country like the Philippines which experiences half the year in the rainy season is the roof gutter details.
From the exterior the presence or absence of the gutter defines the roof line of the house and contributes to the beauty and character of the design in a subtle but important way. Functionally it is the conduit for rain water which bears on maintenance issues for the users in the future.
The most common is the standard gutter design found at the end of the roof’s edge or fascia. This can be in metal or concrete and even bamboo with downspouts bringing the water to ground level.
Illustrated next is the hidden gutter and gutterless types that the practice has designed.
The following is a concrete hidden gutter used with a longspan roof. For this house the client wanted a gutter that will be very durable, and strong. They were for using a concrete gutter with waterproofing and further made durable with a stainless steel lining. To meet this requirement a hidden gutter was done that would be supported by the roof beams. The gutter line would be along the exterior of the wall face so that incase of leaks water would fall outside the house walls.
In the images above you can see from the flashings where the gutter start and where it ends always in the direction of the flow of rain water and bent to deflect water blown up by winds and to discourage birds from nesting.
For the next example the design was for a concrete hidden gutter, but it was decided later that a gutterless design be done, a simple trench on the ground will collect water as it fell. This was because the client preferred to not have maintenance issues for roof gutters, and because the project had a wide lot where a trench would not be a problem.
The roof material used were Japanese style roof tiles that were flat, the clay tiles were installed in such a way so that their shape provided the necessary termination at the roof’s fascia.
A special detail was done to allow water that may seep into the roof tile on to the secondary undersheet roof and to flow out the double fascia
In the last example the gutterless roof is used together with Spanish style roof tiles. As in the previous example the site allowed for trenches on the ground that coincided with the client’s wish for less issues for maintenance.
Because of the roof tiles’ undulating shape the additional metal accessory used was the bird stopper, installed at the end of the fascia to prevent birds from entering the opening of the roof tiles.
Though a thinner roof line was desired, a structural condition in the lower roof made the profile thicker, and this was carried over to the upper roof.
In conclusion the roof gutter whether on the roof’s edge, hidden or on the ground, presents architectural, structural and plumbing challenges that must be addressed by the designer and client. It helps add to the beauty of the design, and bears on the type of maintenance the client prefers for their roof. Lately with the greater acceptance of green building practices like rain water harvesting, this detail will be more important because it will help in the collection of free water for use by house occupants.