Why these small roofs matter
A front porch roof may be only a few feet deep, but it drains directly onto the steps and walkway in front of the door. A patio cover drains onto the patio where people sit. The main roof eave above a deck drops water onto deck boards and splashes it against the house. Without gutters, these areas are wet after every rain, and in cold climates the drips freeze into ice on steps and walkways. Slips and falls on wet or icy steps are a common household injury. See gutters for aging in place.
Porch roofs
Porch roofs are often low-slope or shed roofs attached below the main wall. They may have shingles, metal or a membrane. A small gutter along the front edge, with a downspout at one corner routed away from the steps, keeps the entry dry. On historic homes, porch roofs sometimes have built-in gutters in the cornice that need relining. See gutters for flat and low-slope roofs and box gutters on old homes.
Where the main roof drains onto the porch
On many houses, the main roof drains onto the porch roof below. The water then crosses the porch roof and pours off its edge, often right at the steps. A downspout from the upper gutter that empties onto the porch roof should have a diverter to spread the water, or better, be extended down past the porch roof to the ground. The porch gutter must be sized for any water it receives from above.
Decks
Where a deck sits below an eave without a gutter, roof water falls on the deck boards in a line, wearing the finish, soaking the wood and splashing dirt and water onto the house wall and the ledger board where the deck attaches. Water at the ledger is a common cause of deck rot and failure. Gutters above decks keep water off the boards and the ledger. Downspouts should not empty onto the deck; route them down a post or along the house to the ground and away from the deck footings.
Patio covers and pergolas
Solid patio covers made of aluminum, wood or polycarbonate concentrate water at their low edge. Many manufactured patio cover systems include integrated gutters; add-on gutters work on others. Pergolas with retractable or fixed covers need the same planning. Downspouts often run down a support post and should discharge onto gravel, a splash block or a drain away from the patio.
Sunrooms and screened porches
Sunrooms and screened porches have their own roofs, often low-slope with glass or panels. Water running off them should not pour onto entry steps or the deck. Small gutters, sized to the roof area and connected to downspouts that leave the area, keep these rooms dry and prevent stains on glass and screens.
Ice and safety
In cold climates, any drip above a walkway becomes ice. Fixing overflow above doors, rerouting downspouts that cross walkways, and in some cases adding heat cables to the gutter above an entry prevent ice where people walk. See heat cables for gutters.
Sizing and materials
Small roofs usually need only a 5-inch gutter and a single 2x3-inch downspout, but the gutter must be large enough for any water arriving from an upper roof. Match material and color to the main gutters for a consistent look. On wood porches and decks, keep downspouts and splash away from wood posts and skirting. See how to choose gutter color.
Rain chains as an option
On covered porches, a rain chain can replace a downspout and add a decorative touch. It works best where splash lands on gravel or a basin away from steps and wood. In heavy rain it splashes more than a downspout. See rain chains vs. downspouts.
Protecting deck ledgers and posts
The ledger board, where a deck attaches to the house, is one of the most important structural connections on a deck and one of the most vulnerable to rot. Roof water running down the wall behind the ledger or splashing up from the deck keeps it wet. Gutters above, proper flashing over the ledger and downspouts that keep water away from posts and footings extend the deck’s life. If you see dark staining or soft wood at the ledger, have it checked.
Stone and concrete patios
Water falling on patios from the roof edge stains pavers and concrete, erodes joint sand and can heave pavers when it freezes. A gutter above the patio and a downspout that discharges beyond the paved area keep the surface clean and stable. Patios should also slope slightly away from the house so any water that lands on them drains outward.
Front steps without a porch roof
Some entries have no porch roof at all; the main roof eave runs directly over the front steps. Water from that eave falls right where people stand at the door. A gutter on that eave is essential, and its downspout should be placed so it does not discharge onto the steps or walkway. If the eave is short, consider a small canopy or awning with its own gutter above the door.
Adding gutters when you build
If you are adding a porch, deck or patio cover, plan the drainage with it: where the roof water goes, where downspouts will run and where they discharge. It is much easier to include a fascia board and downspout path during construction than to add them later. See gutters for garages, sheds and outbuildings.