Rat_Hole_Perservation_Plan_1.pdf

Rat Hole Cabin Historic Site, Uintah County, Utah (U21WN0597) 1

Excerpt from Condition Assessment and Preservation Plan for the Rat Hole Cabin Historic

Site, Uintah County, Utah (U21WN0597) by Diederichs and Fisher 2022

PRESERVATION PLAN

Rat Hole Cabin is in need of short-term and long-term preservation intervention. Recommended structural conservation treatments and the materials necessary to implement those treatments are outlined in this section. A few proposed treatments are presented as optional because they involve ground disturbance or restoration, actions that could impact the integrity of Rat Hole Cabin. Also recommended are visitor management actions and site monitoring. Natural erosion poses little threat to the site and does not require treatment at this time. Definition of treatment types and descriptions of their implementation can be found in the Methodology section of this report.

Halting the structural collapse of the main cabin (Feature 1) and the barn (Feature 3) is the most urgent priority. These structures should be stabilized within a year to prevent the loss of substantial portions of the buildings. In addition, weather proofing and stabilizing the granary (Feature 4) is a high priority, requiring action within the next three years. The cellar (Feature 2) and smaller cabin

(Feature 5) are moderate treatment priorities which should be addressed within the next five years.

The instability of the collapsed and or collapsing construction material in Features 3 and 5 pose threats to visitor safety. It is recommended that visitors be deterred from entering both buildings through signage and/or closure.

Table 3. Treatment Priority for Standing Structures at Rat Hole Cabin.

Feature Condition Summary Safety Hazard Treatment Priority

1 Good/ Threatened Moderate Urgent

2 Fair Low Moderate

3 Good/ Threatened High Urgent

4 Excellent Moderate High

5 Fair High Moderate

6 Poor Low None

Feature 1 Treatments

Structural stabilization is urgently needed to keep the south wall, the north wall, and roof of Feature

1 from collapsing within the next decade. This treatment will require realignment of the south, north, and a portion of the interior dividing walls and replacement of the rotting basal logs in the south and north walls of the east room and the south wall of the west room. Wall realignment and basal log replacement should be done in several phases.

Structural Stabilization South Wall and Dividing Wall: The slumping west end of the south wall should be addressed first. It should be jacked up into place from the exterior using the third beam and door jamb. The two rotted basal courses should be cut away and replaced. If possible, the crowns of the logs should be left in place. This will require chopping out the damaged section and splicing in a new log fastened with lag bolts to the intact portion of the old one along a scarf joint.

The replacement logs should be 10-11” diameter and 6-7’ long. Once the wall is lowered onto the replacement beams, the door jamb should be fastened to the new logs with nails.

The leaning middle of the south wall and leaning south half of the dividing wall will need to be realigned together. This will require supporting and lifting the south side roof via jacks in the interior dividing wall entryway and exposed roof supports in the east room. A wood support should

Rat Hole Cabin Historic Site, Uintah County, Utah (U21WN0597) 2 be nailed to the dividing wall beam ends exposed in the middle of the exterior south wall. From this crux point, the leaning south and dividing walls should be winched and jacked back to plumb and the roof lowered onto the wall. To ensure the walls do not again lean out to the south, the two upper roof support logs should be lag bolted together at the upper corner of the doorway gap, at the southwest corner of the west room, and through the window lintel in the east room south wall. The west room south window should then be tacked to the adjacent logs.

Structural Stabilization North Wall: The leaning east and west end sections of the north wall should also be reset and fastened in place. The roof line above the leaning sections has not settled in either location so the resets will not require the roof to be lifted or supported during the reset. To reset each section, a piece of plywood and two overlaying boards should be tacked to the exterior of the leaning wall section. Angled jacks and winches should be used to move the wall back to a plumb position. To hold the west room’s north wall in place, the logs should be tacked to the windowsill with nails and tied to the roof plate and corner v-notch with lag bolts. Similarly, the leaning sections of the east room’s north wall should be fastened to the roof plate with lag bolts.

Basal Log Replacement: Basal logs in the south and east walls of the cabin’s east room are severely rotted and should be replaced. This should be done after structural stabilization has been implemented. Because sediments have built up against the exterior of south and east walls of the cabin, the basal logs should be replaced from the interior. Logs can be brought into the room through the east wall door. The two rotted basal courses should be cut away except for the crowns which should be left in place. This will require chopping out the damaged section and splicing in a new log fastened with lag bolts to the intact portion of the old one along a scarf joint. The two replacement logs should be 10-11” in diameter and 22’ and 17’ long.

Basal Log Treatment: Several basal logs suffering from dry rot in the south, east, and north walls will be left in place as they are not currently impacting the structural stability of the cabin. These logs should be treated with a borate solution to slow down their deterioration (see Methodology section).

Optional French Drain: To further extend the life of the cabin’s basal logs, french drains could be installed along the north and south walls of the cabin below the drip lines (see Methodology section). Drywells could be installed at the western end of each french drain or the drains could be configured to share a single drywell installed off the southwest corner of the building.

Weather Proofing: Wind and direct precipitation are contributing to the structural instability and deterioration of Feature 1. Following National Preservation Guidelines (USDI 1983, 1985, 2004), only the standing elements (walls, roof, floor) of the structure are to be preserved to establish basic weather resistance for the building. The missing doors and windows of the cabin will not be closed or replaced.

The cabin is currently missing half the tar paper corrugated metal roofing and most of its roof cap. These elements should be replaced across the exposed roof. New tar paper should be laid down the pitch of the roof and horizontally across the roof slope with a 5” overlapping seam. Corrugated galvanized tin in 2’ x 6” sheets should be used to cover the exposed portions of the roof with 6” overlaps with sheets below and 4” overlaps with sheets to the side. Galvanized roofing nails can be used to tack the tar paper and corrugated tin to the roof.

There are at least seven suitable original corrugated roofing sheets in a pile north of the structure.

Another twenty 6’ long sheets of galvanized tin will be necessary to finish the roofing. Once the corrugated sheets are in place, the section of ornate roof cap on the ground on the south side of the cabin can be re-fastened to the west end of the roof line to brace the tin roofing from the

Rat Hole Cabin Historic Site, Uintah County, Utah (U21WN0597) 3 prevailing wind.

Finally, exterior walls of Feature 1 should be repointed with daub to seal them from wind and precipitation driven deterioration. The new daub mix will replicate the original soft gray silt and lime daub, rather than the hard yellowish repoint daub, for several reasons. First, the original grayish daub is a more appropriate material than the later yellowish daub over pointing. The grayish daub has not separated from the face of the logs suggesting that it swells and contracts at the same rate as the logs unlike the yellowish over point daub. Because the gray daub is softer lime-based material, it pulls moisture from the adjacent logs. In contrast the yellow over point daub is a hard cement-based mixture, which is likely trapping moisture inside the logs exacerbating their dry rot deterioration. Second, repointing with grayish daub will restore a sense of the 1930s and 1940s look to the cabin. This daub will be slightly recessed to provide a sense of age and deterioration.

Any intact yellowish daub in the cabin joints will be left in place to convey the later repointing.

Feature 2 Treatments

Repoint and Clean Up: The pile of cottonwood stumps and tin on the north side of the structure should be removed to increase the interpretability of the building. Bushes and shrubs growing directly adjacent to and on masonry walls should be cut back. To prevent the loss of the remaining masonry, all exposed wall faces should be repointed with mortar. This mortar will be made of local alluvial silt and lime to replicate the original construction mortar. This will provide at least a decade of stability to the standing masonry, but care should be given to recess the mortar joints to preserve the eroded appearance consistent with state of the cellar. The collapsed masonry walls are considered stable and do not require preservation.

Feature 3 Treatments

Basal Log Replacement: Because the barn roof is suffering from critical structural instability, only the most compromised (east wall) basal log is recommended for replacement. Because sediments have built up against the exterior of the east wall, the basal log should be replaced from the interior.

The upper wall should be supported in place with jacks attached to exterior log ends. The rotted sections of the east basal log will be cut away, leaving the crowns in place. A section of new log will be spliced in and fastened with lag bolts to the intact portion of the old log along a scarf joint.

The replacement log should be 11” in diameter and 12’ long.

Basal Log Treatment: Settling of the structure can be slowed by treating the basal log dry rot with borate. The sleeper and sill logs of the barn should be treated with a borate solution from the interior to slow down the dry rot process (see Methodology section).

Optional French Drain: To further reduce dry rot, french drains could be installed along the east and south walls of the barn (see Methodology section). Because the grade slopes away from the southeast corner of the building, each drain would require its own drywell.

Structural Stabilization Roof: The roof of Feature 3 is critically unstable and should be dealt with in several ways to prevent the complete loss of the roof and threats to visitor safety. Stabilization should begin with the foundation and walls of the barn. To better support the northeast and northwest corners of the loft, the supporting posts, should be shifted back under the structure and fastened in place. One at a time, the sill logs near each corner should be jacked up to unweight the support log. The log should then be shifted to the southeast so that it is directly under the corner of the loft. This may require reseating the posts in their post holes. Finally, the loft should be lowered onto the support beams and tacked in place.

Rat Hole Cabin Historic Site, Uintah County, Utah (U21WN0597) 4

All rafters properly seated in collar joints in the roof plate should be nailed to the roof plate at the collar joint. Next, the displaced roof plate at the south end of the east wall should be rolled back into place and the associated rafters reset in their collar ties. To do this, a board can be screwed across the butt end of the displaced rafters and used to jack up the rafters 3”. The roof plate log should then be rolled back into an upright position and lag bolted to the beam below it. The rafters will be lowered onto the rafter plate so that the notches in each board drop into their corresponding collar plate and nailed in place.

To reinstate some of the structural support originally provided by the loft, at least six new loft joists should be installed. Like the original joists, the new joists will be 12’ long 2” x 6” boards. To insert the new joists, the arched loft sill log can be pushed down with wooden wedges and the boards threaded through the joist notch and across the building to the corresponding joist notch. Once installed, the joists should be tacked in place which will reduce flex in the upper walls.

Next, the four standing sets of rafters in the south half of the building should be reinforced. This entails nailing similar sized 2” x 4” boards on to the existing rafter to create a double beam. These support boards should be about 9’ long and extend from the peak of the structure to just above the roof plate. Boards should be nailed to both sides of the cracked rafter to provide additional triple beam support. Likewise, an additional pair of cross braces should be nailed to the rafter support beams on the central cracked rafters.

The BLM could leave the collapsing roof elements in place to provide some weather protection for the rest of the structure. This tact comes with the recognition that the north half of the roof will eventually collapse and that it poses some safety concern. While the roof stands, a warning sign should be posted next to the north entry way explaining the instability and the inherent risk of entering the structure.

Optional Roof Reconstruction: The north half of the roof is beyond repair, but it could be replaced.

Though restoration of the roof would impact the integrity of the structure the BLM should consider it as a viable option. Restoration of the roof would a) additionally support the intact south half of the roof, b) protect the interior of the building from weather, and c) remove the safety threat posed by the collapsing north half of roof.

Before the north half of the roof can be rebuilt, the collapsed section should be removed. Scaffolding should be erected to allow the collapsing roof to be cut into manageable pieces and lowered to the ground. The broken rafters and purlins should be disposed of, but the corrugated tin can be salvaged and reused.

Restoration would begin with the construction of three new rafters built in the same fashion as the standing rafters. These rafters are built with 9’ long 2” x 4” lumber supported by 1’6” cross braces attached just below the peak. Nine 11’ long 1” x 12” boards will be nailed across the rafters as purlins. The salvaged sheets of non-galvanized corrugated tin would be nailed directly to the purlins from below as sheathing.

Weather Proofing: Wind and direct precipitation are contributing to the structural instability and deterioration of Feature 3. Following National Preservation Guidelines (USDI 1983, 1985, 2004), only the standing elements (walls, roof, floor) of the structure will be preserved for the purposes of weather resistance. The collapsed roof, missing doors, gable sheathing, and interior wood chinking will not be replaced.

The first story exterior walls should be repointed with daub to seal them from wind and precipitation. The new daub mix will replicate the original soft gray daub visible in the walls.

This mix will be similar to that used to repoint Feature 1. This process will help weatherproof the

Rat Hole Cabin Historic Site, Uintah County, Utah (U21WN0597) 5 lower story of Feature 3 and restore a sense of the 1930s and 1940s look and feel of the barn. This daub will be slightly recessed to provide a sense of age and deterioration.

Visitor Management: Modern trash inside Feature 3 should be removed. The saying incised into the daub in the north exterior wall and the pencil inscriptions on the south wall logs should be left in place. While the saying may be recent vandalism, there is a chance it was inscribed during the ranching era. The pencil inscriptions on the log in the south wall could provide insight into specific uses of the barn and the work of a cowboy at Rat Hole Cabin. They should be left in place and considered a resource for future investigations.

Feature 4 Treatments

Roofing: Roof collapse is the only imminent threat to Feature 4. It is recommended that collapsed roof tin be gathered from the vicinity of the building and tacked back onto the roof to protect the interior and walls of the granary from the elements. An 11’ long purlin board can be added if necessary to support the west side roof tin. This board should be a 1” x 6” board to match the historic ridgeline beams.

Feature 5 Treatments

Given the collapsing state of the Feature 5 cabin the structure will continue to deteriorate over the next decade. A few measures should be taken to slow this process and provide visitor safety.

Weather Proofing: All four exterior walls should be repointed with daub to adhere the interior chinking in place and provide structural support to the log walls. This daub will mimic the original daub in the cabin walls, which is composed of local silts and gravels from the flood plain mixed with lime.

Safety Closure: As a safety precaution, the interior of cabin Feature 5 should be closed to visitors.

Rough cut aged boards should be nailed across the south wall doorway to a height of 4’. This will allow most visitors to see into the structure but stop them from entering the building. It has the added benefit of tying the east and west halves of the south wall together, increasing its stability.

Structural Stabilization Materials

A variety of materials are necessary for structural stabilization of the standing buildings at Rat Hole

Cabin (Table 3). These materials will be obtained from three sources 1) commercial hardware outlets, 2) salvaged construction materials on site, and 3) natural materials collected from the site vicinity.

Table 3. Materials Necessary to Implement the Proposed Treatment Plan.

Features Count/ Pounds/ or

Square Feet Material

1 14 New galvanized corrugated tin 2’ wide 12’ long

1, 3, 4 7 Reuse galvanized corrugated tin 2’ wide 6’ long

1, 4 6 Reuse non-galvanized corrugated tin 2’ wide and 12’ long

1, 4 3 pounds Galvanized roofing nails

1, 3, 4, 5 2 pounds Galvanized 3” nails

1, 3 150 square feet Tar paper in roll

1, 3 12 Lag bolt 12” long 1 12 Lag bolt 18 “long

1 1 pounds Brads 2”

Rat Hole Cabin Historic Site, Uintah County, Utah (U21WN0597) 6

1, 3 5 Lumber 2” x 4” 6’ long

4 4 Lumber 2” x 4” 5’ long

3 10 Lumber 2” x 4” 10’ long

3 10 Lumber 2 x 6 12’ long

Rat Hole Cabin Historic Site, Uintah County, Utah (U21WN0597) 7

Count/ Pounds/ or

Square Feet Material

4 1 Lumber 1 x 6 12’ long

5 5 Rough cut lumber 2 x 6 4’ long

1, 3, 4, 5 360 square feet Borate

1, 2, 3, 4, 5 570 square feet Daub/ Mortar

1, 3 5 Logs 10-11” diameter two 7’ long, one 12’ long, one 17’ long, and one 22’ long Ponderosa Pine or Engelmann Spruce

Optional treatments include the installation of french drains outside of Features 1 and 3 and reconstruction of the northern half of the roof covering Feature 3. The materials required for these optional treatments are listed separately (Table 4).

Table 4. Materials Necessary to Implement Optional Elements of Treatment Plan.

Count/ Cubic Feet/ or Square Feet/ Pounds

Material

1, 3 185 cubic feet Gravel ¾” or larger washed gravel

1, 3 520 square feet Filter Fabric

3 14 Reuse non-galvanized corrugated tin 2’ wide and 12’ long

3 2 pounds Galvanized roofing nails

3 2 pounds Galvanized 3” nails

3 6 Lumber 2” x 4” 9’ long

3 9 Lumber 1” x 12” 12’ long

Most of the needed stabilization materials are commercially available. Purchased materials should be comparable to the historic materials at the site whenever feasible. For instance, new milled and rough-cut lumber should be untreated. There are several commercial borate wood preservative treatments on the market. National Park Service has put forward two borate products (Bora-Care and Tim-Bor) that are mild insecticides but safe for wildlife, plants, and humans. As recommended in the National Park Service Protecting Wood With Preservatives and Water Repellants Conserve

O Gram (NPS 1993), borate products other than these should be approved by the BLM_WRFO.

Both new and re-purposed galvanized roofing tin will be used during stabilization. If the look of the new galvanized corrugated roofing tin is visually different than the historic galvanized corrugated tin salvaged from the site, the new tin can be aged to match the older tin. This is done by scrubbing the protective coating off the surface of the galvanized tin with steel wool, pouring apple cider vinegar across the surface, and letting the tin sit in the sun for two to six days. The vinegar should be washed off the surface of the tin before it is secured to the roof.

Two new Ponderosa Pine or Engelmann Spruce logs are required for the stabilization of the main cabin (Feature 1). Ideally, these logs would come from trees harvested on or nearby the property at least six months before preservation work. If the logs are commercially bought, special care should be taken to match the diameter and grain type of the original logs.

A critical element to the success of the structural stabilization will be creating an appropriate daub/mortar mix. This mix should include hydrated lime, which can be purchased commercially, and silty clay sediment from the Rat Hole Canyon floodplain. The "ideal" constituent makeup should match the original in material makeup and color of the daub/mortar in each building as closely as possible. Below is a list of desirable attributes for stabilization daub/mortar as defined by Metzger (1988):

Rat Hole Cabin Historic Site, Uintah County, Utah (U21WN0597) 8

• Material must be durable with good adhesive qualities, able to withstand open weather exposure without excessive discoloration, crumbling, or extensive cracking.

• Materials must be consistent with variations in the aboriginal mortars throughout the site and be similar in color, texture, and content to the extent possible given availability and durability constraints.

• Materials must be moisture resistant to the extent that they dry and wet without excessive expansion and contraction, such as sediments containing illite or kaolinite, which compromises bonding resulting in poor consolidation and weather resistance.

• Materials must provide adequate flexibility to withstand seasonal wall movement and settling.

• Materials must provide good capillary drainage to allow moisture to escape the walls, preventing interior pooling, which promotes daub/mortar erosion and cracking during freeze/thaw and swell/shrink cycles.

• Materials must exhibit inferior compressive strength and superior porosity to the logs or stones, which they surround, ensuring that the mortar is less weather resistant than the original wall material. If the added material is "harder" than the wall material will experience accelerated fabric decay.

• Materials should be removable without permanent adverse impact to the resource.

Most of the original daub and mortar at Rat Hole Cabin is a mix of greyish silty clay alluvial sediments and lime. The silty clay alluvial material is readily accessible in the cut bank of Rat Hole

Creek off the southwest edge of the site. This material should be collected from an exposed slope away from any site features and the location should be rehabilitated after collection. To determine the proper mix of lime and sediment for structural stabilization at Rat Hole cabin, various proportions of sediment and lime should be mixed into samples, left to dry, and compared with the original daub/mortar from each structure. The best match sample mixes will have the same proportions of grain size, tensile strength, color (based on the Munsell color pallet) as the original mortar. Water for the daub/mortar mixes will be obtained from a salt free source, such as a municipal water system.