Why manufactured homes need gutters
Manufactured homes usually sit on piers or blocks with skirting around the base, and the space under the home is a crawl space in all but name. Roof water that falls off the eaves lands right at the skirting and runs underneath. Over time that can:
- soften the soil under piers and anchors, contributing to settling and an out-of-level home;
- keep the crawl space damp, inviting mold, rot in the floor system and pests;
- rot wood skirting, steps, decks and porches built against the home;
- erode the yard and wash out gravel pads along the drip line;
- splash mud and water onto siding and windows.
Gutters carry that water to downspouts and away from the home. See downspouts and your foundation.
Roof shapes and edges
Manufactured homes often have low-slope roofs, sometimes metal, sometimes shingle, with short overhangs and thin fascia or none at all. Older single-wides may have rounded metal roofs with a drip rail at the edge. That affects how gutters attach. Common methods include:
- Fascia-mounted hidden hangers where there is a solid fascia or rim to screw into.
- Roof straps fastened under the roofing, where the edge has no fascia; on metal roofs, straps must be sealed against leaks.
- Brackets fastened to the wall or rim joist for half-round or K-style gutters.
Industry work specifications for manufactured housing, such as the National Renewable Energy Laboratory’s Standard Work Specifications, call for gutters sized for the area drained, attached with screws or other mechanical fasteners, sloped toward downspouts at least about 1/4 inch per 10 feet, and sealed watertight at seams.
Sizing
A double-wide roof can easily be 1,500 square feet or more, draining to two long eaves. Low-slope roofs deliver water to the gutter more slowly, but long runs still need enough downspouts. 5-inch gutters are common; in heavy-rain areas, 6-inch gutters and 3x4-inch downspouts are worth considering. See downspout size and placement.
Downspouts and skirting
Downspouts should discharge well away from the skirting, at least several feet, onto ground that slopes away. Avoid discharging next to piers, steps or utility connections. Extensions, splash blocks or buried lines to a daylight outlet work. If the home sits in a community with shared drainage, ask management where water may go.
Snow and wind
In snow country, low-slope roofs hold snow longer, and metal roofs shed it suddenly. Strong hangers at close spacing help; on metal roofs, snow guards protect gutters from sliding snow. Manufactured homes in windy areas need gutters and downspouts fastened securely so they do not become loose debris in storms. See gutters and high winds and snow load and gutters.
Materials
Seamless aluminum is the most common choice: light, rust-resistant and available in many colors. Vinyl kits are inexpensive but can become brittle and sag in sun and cold. Steel is stronger but heavier. Match fasteners to the gutter and roof metals to avoid corrosion. See gutter materials compared.
Roof leaks and gutter installation
Manufactured home roofs, especially older metal roofs, can be sensitive to penetrations. Any fastener through the roof must be sealed. If the roof needs a coating or recover, coordinate gutter work so the roof edge is finished first. See new roof, new gutters?
Porches, decks and carports
Many manufactured homes have site-built porches, decks and carports added later. These often have their own low roofs that drain onto steps and walkways. Small gutters on these roofs, with downspouts routed away from steps, prevent ice and rot. See gutters for garages, sheds and outbuildings.
Crawl space moisture and skirting vents
Skirting usually has vents to let moisture escape from under the home. When roof water pours along the skirting, it can enter through vents and gaps and pool on the ground under the home. A vapor barrier on the ground helps, but it cannot keep up with water flowing in from outside. Keeping roof water away from the skirting is the first step; checking that the ground under the home slopes to drain is the second. Damp crawl spaces under manufactured homes lead to sagging floors, mold on the underside of the floor system and pest problems. See gutters and pests.
Piers, anchors and settling
Manufactured homes rest on piers and are held down by anchors and straps set into the ground. Soil softened by repeated wetting can let piers settle and anchors loosen, so floors go out of level and doors start to stick. Roof water dumped along the same side of the home in every storm is a common cause. Gutters with downspouts that carry water away keep the soil around piers and anchors more stable. If you notice doors sticking or floors sloping, have the home releveled and check where roof water goes before the problem returns.
Older single-wides
Older single-wide homes often have rounded metal roofs with a narrow drip rail at the edge and no fascia at all. Gutters on these homes are typically hung from brackets screwed into the wall framing or from straps under the roof edge. Because the walls are thin, fasteners must hit framing, not just the siding. An installer familiar with manufactured homes will know where the framing is and how to seal fasteners on the metal roof.
Communities and park rules
In manufactured home communities, the lot, drainage and sometimes exterior changes are governed by park rules. Ask management before installing gutters, especially about downspout discharge and colors. Some communities encourage or require gutters because runoff affects neighboring lots and shared roads.
Costs
HomeGuide puts seamless aluminum gutters at about $6 to $12 per linear foot installed nationally. A single-wide may need only two runs; a double-wide, more footage and downspouts. Roof straps, fascia boards or brackets can add cost. See our cost guide.
Checklist
- Is there a solid fascia or rim to attach to, or are straps or brackets needed?
- How will fasteners through the roof be sealed?
- Are gutters and downspouts sized for the roof and local rain?
- Where will each downspout discharge, away from skirting and piers?
- Do porches, decks or carports need their own gutters?
- Are snow guards or extra hangers needed?