McCall Timberframe Livestock Shed

Designed for the Environment and Built for a 100 Year Life

Designing a Passive Structure for a Mid-Latitude, High-Elevation Hay Meadow. This livestock shed is designed to work with the natural conditions of the site using traditional, passive methods. It is intended to last 100 years.

The livestock shed at the start of its second winter in McCall, Idaho. Icelandic sheep, sheared in the fall, are already toasty warm in their new and lengthening winter coats. One winter down, 99 winters to go. With proper maintenance, this shed will go the distance.
The livestock shed at the start of its second winter in McCall, Idaho. Icelandic sheep, sheared in the fall, are already toasty warm in their new and lengthening winter coats. One winter down, 99 winters to go. With proper maintenance, this shed will go the distance.
The livestock shed at the start of its second winter in McCall, Idaho. Icelandic sheep, sheared in the fall, are already toasty warm in their new and lengthening winter coats. One winter down, 99 winters to go. With proper maintenance, this shed will go the distance.

Challenging Building Site Provides Opportunities. The building site is a hay meadow cleared of forest in the 1800s. It is situated at about 44.9 degrees north and about 5,000′ elevation.

Prevailing winds are from the west and range from southwest to northwest. There are few trees nearby, which means wind can be significant and sunlight is abundant throughout the day.

Concrete footings and piers lift the shed well above the surrounding ground to provide for dry feet for farmer and livestock.
Concrete footings and piers lift the shed well above the surrounding ground to provide for dry feet for farmer and livestock.
Concrete footings and piers lift the shed well above the surrounding ground to provide for dry feet for farmer and livestock.

The hay meadow is sub-surface-irrigated in the summer using trenches that were hand-dug generations ago and bring water from the nearby river. Irrigation water spreads laterally through the soil from the ditches to irrigate the whole meadow, including the site for the shed.

The soil is a sandy loam that extends about 2 feet down where it is replaced by natural river cobbles, gravel and sand. The soil layer retains water, while the layers below it are very well drained. Groundwater during irrigation season can approach to two feet from the surface. In winter, groundwater drops to below 40 inches. The frost line as defined by local building code is two feet below the surface.

Layers of local river rock and gravel bring the shed floor above the surrounding ground and provide drainage of the shed floor. Maintenance is easy: in summer the straw bedding is removed and composted, the gravel floor is rinsed in place as needed and re-raked.
Layers of local river rock and gravel bring the shed floor above the surrounding ground and provide drainage of the shed floor. Maintenance is easy: in summer the straw bedding is removed and composted, the gravel floor is rinsed in place as needed and re-raked.
Layers of local river rock and gravel bring the shed floor above the surrounding ground and provide drainage of the shed floor. Maintenance is easy: in summer the straw bedding is removed and composted, the gravel floor is rinsed in place as needed and re-raked.

Winter snow loads on the roof can be up to 120 pounds pr square foot. Humidity can be very low and sunlight intense, which causes exposed wood to shrink, crack and warp.

Design Goals: The livestock shed must be crafted to withstand the seasons for 100 years. The floor area must be dry, provide for drainage and be easily maintained. The main entrance must be shielded from the wind and provide an outdoor area out of the wind for livestock. Snow shedding from the roof must shed away from the area favored by livestock. One half of the shed must provide a sunlit and well-ventilated area for the animals, the other half must provide cool, dry storage for hay that is out of direct sunlight. Locally-sourced, solid-sawn materials are preferred for construction.

Hand-cut tenons on native timbers harvested locally.
Hand-cut tenons on native timbers harvested locally.
Hand-cut tenons on native timbers harvested locally.

Taking advantage of Mid-Latitude Sunlight: The site lies at 44.9 degrees north. This means that solar heat and light from the sun will be on the southern wall of the shed during winter, and higher overhead during the summer. Because solar heat and light are desirable in winter, the windows of the shed are located on the southern portion of the building. Likewise, the eaves are short to allow maximal winter heat gain on the eastern, southern and western walls. The northern portion of the building does not have windows because windows on the north will act more as a place where heat is lost. In addition, hay is stored in the northern half of the building and the livestock are bedded on the southern half of the building. This keeps the hay out if direct sunlight and on the cooler side of the building, which helps keep the hay in its best condition, while the livestock enjoy the sunny, southern side of the building. Sunshine during the summer comes from overhead and is intercepted by the roof.

Oriented for the Wind: Normally in this latitude, the long axis of the building would be faced towards the south to maximize winter solar heat gain along the longest wall. This means the ridge of the roof would be oriented east-west. However, in this situation, the need for a wide entrance and a wide area for the livestock to be sheltered from the westerly wind meant that the ridge of the roof was situated to run north-south.

Planning for Shedding Snow: In this area of McCall, snow fall is significant. There are two approaches for heavy snow loads on roofs: keep it on the roof as much as possible, or get it off the roof as much as possible. Keeping snow on the roof provides insulation and minimizes risk and damage from snow shedding from the roof. Shedding snow off the roof minimizes ice-damming, leaks, and long-term strain on roof timbers from the snow’s weight which can cause sagging of timbers. It was decided for this project to get the snow off by setting the roof pitch steep enough and using metal roofing to allow the snow to slide off. The roof pitch is also shallow enough so that if it is desired in the future to use the snow retention approach, snow anchors can be added to the roof surface. The roof was designed to shed snow to the east to protect the livestock area in the lee of the shed on the western side.

A Solid Foundation, Dry Feet, Dry Timbers, Easy Floor Maintenance, and Increased Summer Ventilation: The farmer and the livestock want dry feet in the shed throughout the year. Control of air flow is necessary in winter and is to be maximized in summer. And, framing timbers must be kept well clear of dampness.

Hand-cut mortise and tenon joinery make for strong, traditional connection between timbers. These barn joints are cut for function not appearance, but they are lovely.
Hand-cut mortise and tenon joinery make for strong, traditional connection between timbers. These barn joints are cut for function not appearance, but they are lovely.
Hand-cut mortise and tenon joinery make for strong, traditional connection between timbers. These barn joints are cut for function not appearance, but they are lovely.

The strategy chosen was to use a timber-frame structure on a post and pier foundation system with a gravel floor and large, sliding doors on the windward and leeward sides of the shed.

Exterior walls were designed to be suspended on the timber frame slightly above finished floor height to facilitate the stack effect in summer, which brings fresh air in on windless summer days, and to allow easy replacement of the lower portions of the exterior walls as snow, soil moisture, and the effects of livestock degrade the lower walls over the years. The lower two foot portion of the exterior walls was constructed as separate assemblies from the upper exterior walls so as to be easily replaceable. The gap between the exterior walls and the gravel floor is regulated in winter using straw bedding.

The footings were set as deep as appropriate given the groundwater level, and concrete piers were used to lift the shed. Layers of local river cobbles and gravel were placed to cover the footings for additional frost protection and to bring the floor level well above the surrounding grade.

Assembling the timber frame in sections using a traditional, low-cost method: a gin pole and block and tackle.
Assembling the timber frame in sections using a traditional, low-cost method: a gin pole and block and tackle.
Assembling the timber frame in sections using a traditional, low-cost method: a gin pole and block and tackle.

Locally-Sourced Timbers: The frame of the shed was crafted with timbers harvested and sawn by a local sawyer.

Solid-sawn natural timbers will move quite a bit as they dry after harvest and during seasonal changes. Hand-cut joints were sized to allow some play. Joints were secured with stout maple pegs.

High-quality plywood sheathing and roof decking make for a lasting structure.
High-quality plywood sheathing and roof decking make for a lasting structure.
High-quality plywood sheathing and roof decking make for a lasting structure.

Crafting and Assembling the Timber Frame: The joints of the posts and beams of the timber frame are cut while the timbers are on the ground. They are assembled into manageable sections on the ground using wooden pegs, then hoisted into place and joined together using more pegs. Here, the traditional gin pole and block and tackle are used to hoist assembled sections into place. For a project this size, this is a quiet, simple, cost-effective and minimally intrusive method of hoisting assemblies.

Sheathing and Siding: Sheathing with 3/4″ CDX plywood ensures greater longevity than with composite sheathing. Siding is solid-sawn board-and-batten material from local, native trees.

Locally-grown and milled solid-sawn vertical board siding.
Locally-grown and milled solid-sawn vertical board siding.
Locally-grown and milled solid-sawn vertical board siding.

Light Paint Color and Sheet Metal Flashing Protect Wood Against Wind, Aridity and Solar Radiation: At this elevation in this climate, sold-sawn wood is dried and twisted quickly by the elements. Clear coats provide protection and look great but they require frequent maintenance. Dark paint colors are in vogue, but increase solar effects on wood. Here, a top-quality light-colored latex is used for the exterior paint.

Siding boards are pre-painted before battens are installed. Battens are pre-painted on all sides prior to installation. This strategy ensures paint covers wood even when the battens move with the seasons. Boards and battens are hand-nailed with hot-dipped galvanized nails rather than with electro-galvanized nail-gun nails. This ensures best nail positioning and retention.

Sheet metal flashing on exposed timber ends and fascia extend service life.

How Did It Do?: As of 2023, the livestock shed has been through one full winter and one full summer. How did it perform? So far it is doing very well.

Opening both sliding doors and all windows and removing straw bedding from the base of walls provides great ventilation in summer. Closing the windward door and using windows and straw bedding at the base of walls provides a flexible system to regulate ventilation and temperature in winter.

The roof pitch and metal roofing shed the snow gently. Sometimes, the snow pack on the roof curls inwards as it creeps off the downslope eave, but it doesn’t reach the siding. Icicles can form at night on the downslope eave if a sunny day is followed by a clear, cold night. But, no ice-damming or leaking has occurred. This is a good roof pitch for this size of structure in this climate. Wainscot height is adequate to prevent snow pack from touching wood siding. So far, so good.

Hay storage has worked very well also. Our grass hay is unsprayed and hand-cut with scythes at the farm, so our grass hay is a premium product and good storage is valuable. The spring of 2022 was a long time coming. Hay kept in the shed stayed dry and fragrant and the sheep sure loved it. The flock of three ewes birthed three lambs that spring, and the first born in the shed was Jack Frost the ram lamb, April 1st 2022. The air temperature outside was in the 20s but in the shed Jack was warm and toasty.

Jack Frost the ram lamb, first born in the new shed, April 1, 2022. It was in the 20s outside but Jack was warm in the shed on his bed of hand-cut native grass hay.
Jack Frost the ram lamb, first born in the new shed, April 1, 2022. It was in the 20s outside but Jack was warm in the shed on his bed of hand-cut native grass hay.
Jack Frost the ram lamb, first born in the new shed, April 1, 2022. It was in the 20s outside but Jack was warm in the shed on his bed of hand-cut native grass hay.

What To Do Better? The metal wainscot on the exterior looks great but is a roofing grade faux-standing seam profile which is proving inadequate to withstand the rubbing of the sheep, especially during the rut when the ram is at his most active. Future projects should utilize a heavy-gage corrugated roofing profile for exterior wainscot.

Want Help Designing or Building Your Timberframe Shed or Barn? Whether you’re in our area or on the other side of the world, we’re happy to share what we have learned and help however we can.