A construction method for a modern traditional style wooden tile roof

Abstract

This invention relates to the field of roof construction technology, and in particular to a construction method for a modern traditional-style wooden tile roof. The method includes the following steps: re-laying sheathing boards impregnated with preservatives on the roof; grouting the gaps between adjacent sheathing boards; injecting preservatives into the tenon and mortise joints and corners of the sheathing boards; applying protective mortar and allowing it to dry; applying a layer of plaster backing and patting it when it is 70-80% dry; after the plaster backing is completely dry, applying a light gray backing and applying hemp fiber to form knots when it is 80% dry; brushing a nano-composite waterproof layer onto the light gray backing; applying a flame-retardant layer onto the nano-composite waterproof layer; applying shoulder mortar to the ridge; laying the tiles on the flame-retardant layer; and finally, securing the joints and ensuring a tight seal. This invention, using the above steps, improves the waterproof performance of the thatched wooden roof and provides a method for laying the tiles to prevent them from slipping off on steeply sloping roofs.

Description

Technical Field

[0001] This invention relates to the field of roof construction technology, and in particular to a construction method for a modern traditional style wooden structure tile roof. Background Technology

[0002] Ancient Chinese architecture is an important part of traditional Chinese culture, and its architectural color art is its most distinctive feature. It has always exuded a magical charm, and through more than two thousand years of historical development, the understanding and application of ancient architecture have been continuously deepened. Traditional style wooden tile roofs are often used in modern architecture to create unique architectural styles; however, existing methods for constructing wooden tile roofs have many problems.

[0003] Traditional thatching techniques are often used in large-scale projects such as modern-traditional style architectural complexes, temples, and gardens. With the development of modern materials science and building technology, new materials and technologies are gradually being applied to thatching. Despite the use of new materials, some still present problems in practical use. For example, some new waterproof membranes are not compatible with traditional thatching materials, easily leading to delamination and peeling.

[0004] When laying tiles on a roof behind a tarpaulin, the steep slope of the roof makes it difficult for workers to maintain stability. Furthermore, the steep slope means the tiles are more susceptible to gravity and wind forces, making them prone to slipping and shifting. Traditional fixing methods may not be adequate for steep roofs, resulting in insecurely fixed tiles and potential safety hazards. Summary of the Invention

[0005] The purpose of this invention is to provide a construction method for a modern traditional style wooden structure tile roof, and to provide a method for laying tiles that increases the stability of the connection between tiles and at the same time prevents tiles from slipping off when laying tiles on a steep roof.

[0006] To achieve the above objectives, this invention provides a construction method for a modern traditional-style wooden tile roof, comprising the following steps:

[0007] S1. Re-lay the roofing boards after impregnation with preservative, and use small hemp fiber mortar to fill the gaps between adjacent roofing boards. Inject preservative at the tenon and mortise joints and corners of the roofing boards.

[0008] S2. Apply 10-20mm of protective plaster to the sheathing board and let it dry for no less than 8 hours after application;

[0009] After the protective plaster in S3 and S2 has dried slightly, apply the plaster backing in layers. After each layer of plaster is applied, let it dry, smooth it, and compact it. The thickness of each layer of plaster backing should not exceed 50mm. When it is about 70-80% dry, pat the backing.

[0010] After the mortar backing in S4 and S3 is completely dry, apply the blue-gray backing. The thickness of each layer of blue-gray backing should not exceed 30mm. After each layer of blue-gray backing is applied, apply hemp fiber to the surface before applying the next layer. When the blue-gray backing is about 80% dry, apply hemp fiber and make a bend.

[0011] S5. After removing the loose particles on the bluish-gray back in S4, apply an interface agent. After drying, brush the nano-composite waterproof coating in the same direction. After drying again, brush the second layer of nano-composite waterproof coating in a direction perpendicular to the previous one. Allow to cure naturally for 24-48 hours to obtain a nano-composite waterproof layer.

[0012] S6. Apply a flame-retardant coating base layer evenly to the nano-waterproof layer obtained in S5. The application direction is the same as the direction of the second coat of the nano-composite waterproof coating. After the flame-retardant coating base layer dries, apply the flame-retardant coating top layer in a direction perpendicular to the flame-retardant coating base layer. After drying and curing, the flame-retardant layer is obtained.

[0013] S7. Apply mortar to the ridge, lay battens and tiles on the fire-retardant layer, connect the mounting holes in the center of the tiles to the corrosion-resistant steel wires on the battens, connect the tiles to each other with mounting blocks and mounting grooves, set anti-fall blocks on the roof at the bottom of the tiles, and after all the tiles are laid, pinch the joints and fill them tightly.

[0014] The roof is inspected and accepted after construction is completed. If it meets the standards, the project is considered finished. If it does not meet the standards, the non-compliant parts are dealt with until the standards are met and the project is considered finished.

[0015] Preferably, in S1, the preservative includes one or more of fish oil, linseed oil, tung oil, and mineral oil.

[0016] More preferably, the mineral oil includes one or more of paraffin oil and naphthenic oil.

[0017] In this invention, a preservative is applied to the new roofboard to prevent corrosion. The preservative can penetrate deep into the fibers of the roofboard to form a protective layer, preventing moisture intrusion and extending the service life of the roofboard.

[0018] Preferably, in S2, the protective ash includes white lime, blue lime, and additives mixed in a mass ratio of 100:8:3-8.

[0019] Preferably, in S3, the mortar backing comprises lime and loess mixed in a mass ratio of 1:3.

[0020] Preferably, in S3, when applying the mortar backing, the mortar backing at the eaves and ridge can be slightly thinner, and if the mortar backing at the middle section is too thick, the roof tiles can be flipped over onto the protective mortar to reduce the roof load.

[0021] Preferably, in S4, the bluish-gray backing comprises white lime, bluish-gray, and additives mixed in a mass ratio of 100:8:3-8.

[0022] Preferably, in S4, the process of sticking hemp and making the "knots" involves using a wooden stick with a semi-circular tip to make several shallow circular indentations on the bluish-gray back. Every five indentations form a group of "knots," and hemp is stuck between each group of "knots."

[0023] Preferably, in S5, the nanocomposite waterproof coating includes one or more of the following: water-based acrylic emulsion, nano-silane, nano-silica, nano-zinc oxide, nano-fluorocarbon, dispersant, and plasticizer.

[0024] The dosage of nano-composite waterproof coating is 0.6-1.5 kg / m².

[0025] In the nanocomposite waterproof coating provided by this invention, the total mass of nanosilane, nanosilica, nanozinc oxide, and nanofluorocarbon accounts for 2-5%. The nanomaterials form a hydrophobic surface on the bluish-gray backing, increasing the waterproof performance.

[0026] Nano-silanes can penetrate deep into the blue-gray backing to form a deep waterproof layer while maintaining breathability. Nano-silanes bond well with the blue-gray backing and exhibit strong durability. Nano-silica forms a dense hydrophobic layer on the surface of the blue-gray backing, providing excellent waterproofing. Nano-fluorocarbons, combined with nano-silica, form a superhydrophobic surface with excellent waterproofing, strong weather resistance, stain resistance, and easy cleaning. Nano-zinc oxide possesses hydrophobic and antibacterial properties, inhibiting mold growth on the blue-gray backing.

[0027] Preferably, in S7, the shoulder plastering involves tying a horizontal guideline on the ridge line where the two slopes intersect. The bottom of the ridge is plastered along this line, with the plastering height being straight with the horizontal guideline and the plastering width being 300-500mm. The horizontal guideline is vertically positioned on the plaster back of the front and back slopes on both sides.

[0028] Preferably, in S7, a number of mounting blocks are provided on the top side of the tile, and a number of mounting grooves are provided on the bottom side of the tile, with the mounting blocks and mounting grooves cooperating and connecting.

[0029] Preferably, the additives include one or more of the following: nano-silica, nano-titanium dioxide, hemp fiber, polypropylene fiber, wood fiber particles, bamboo fiber, wheat straw, cellulose ether, and linseed oil.

[0030] In the additives provided in this invention, nano-silica and nano-titanium dioxide reduce the porosity in mortar, and the dense structure improves freeze-thaw resistance and strength.

[0031] The addition of hemp fiber, polypropylene fiber, wood fiber particles, bamboo fiber, and wheat straw increases the tensile strength and toughness of lime mortar, reduces cracking, and thus improves adhesion.

[0032] The addition of cellulose ether can increase the water retention and viscosity of lime mortar, thereby improving its adhesion to the surface of the new slab.

[0033] The addition of linseed oil and tung oil, when used in combination with one or more of hemp fibers, polypropylene fibers, wood fiber particles, bamboo fibers, and wheat straw, effectively reduces the porosity and pore size in lime mortar, improving its mechanical properties and durability.

[0034] Preferably, loess from deeper strata should be selected, and the color of the loess should be uniform. It is advisable to use loess from the same strata in the same region.

[0035] Quicklime is made by slaking quicklime, adding water, and passing it through a fine sieve until it swells. It should be left to stand for 15 days before use.

[0036] Blue-gray is the fine powder from small-sized clay bricks after being sieved.

[0037] Therefore, the present invention employs a construction method for a modern traditional-style wooden tile roof using the above steps, the advantages of which are as follows:

[0038] 1. In the roofing construction method provided by the present invention, the construction sequence is reasonably arranged after analyzing the roof wooden structure, which greatly improves the quality of the project. The protective board mortar provides the necessary rough surface to promote adhesion, the mortar backing enhances the stability and thermal insulation performance of the roof structure, and the blue-gray backing ensures the waterproof function of the roof.

[0039] 2. This invention uses a compound preservative to treat the sheathing board for corrosion protection. The preservative can penetrate deep into the fibers of the sheathing board to form a protective layer, preventing moisture intrusion and extending the service life of the sheathing board.

[0040] 3. The tile and tile laying method provided by the present invention increase the connection stability between tiles and avoid tile slippage when laying tiles on steep roof slopes. The setting of the installation groove and installation block increases the positioning accuracy of tile laying and improves the laying efficiency of tiles.

[0041] 4. This invention uses compounded additives to reduce the porosity of the mortar in the protective board ash and the blue-gray backing, and to increase tensile strength, toughness and adhesion.

[0042] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0043] Figure 1 This is a flowchart of a construction method for a modern traditional style wooden structure tile roof according to the present invention;

[0044] Figure 2 This is a schematic diagram of the roofing of the roof tiles in Embodiment 2 of the present invention;

[0045] Figure 3 This is a schematic diagram of the roof tile in this invention;

[0046] Figure 4 This is a schematic diagram illustrating the connection between the roof tile, the batten, and the corrosion-resistant steel wire in this invention.

[0047] Figure 5 This is a top view of the connection between the batten and the corrosion-resistant steel wire in this invention.

[0048] Figure label:

[0049] 1. Roofing tile; 2. Mounting block; 3. Mounting groove; 4. Water passage hole; 5. Mounting hole; 6. Anti-fall block; 7. Roofing strip; 8. Corrosion-resistant steel wire. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0051] Loess from deeper strata should be selected, and the color of the loess should be uniform. It is advisable to use loess from the same stratum in the same region. Before use, the loess should be sieved to remove foreign impurities and larger loess particles to avoid incomplete water penetration during curing, which would cause inconvenience in construction. The curing time should not be less than 2 days.

[0052] Quicklime is made by slaking quicklime, adding water, and sieving it through a fine sieve. It should be left to stand for 15 days before use.

[0053] Blue-gray is the fine powder from small-sized clay bricks after being sieved.

[0054] Preservatives include one or more of asphalt oil, linseed oil, tung oil, and mineral oil.

[0055] The additives include one or more of the following: nano silica, nano titanium dioxide, hemp fiber, polypropylene fiber, wood fiber particles, bamboo fiber, wheat straw, cellulose ether, and linseed oil.

[0056] The hemp fibers used for the knife should be at least 80mm long. They should be moistened with clean water one day in advance until thoroughly soaked. When using them, they should be loosened, shaken apart, and impurities removed.

[0057] Wheat straw should be smeared with lime water and piled up and smoldered until it becomes soft before it can be used. Before smearing with lime water, it is advisable to flatten the wheat straw with an axe.

[0058] Example 1

[0059] like Figure 1As shown, this invention provides a construction method for a modern traditional-style wooden tile roof, including the following steps:

[0060] S1. Re-lay the roofing boards after impregnation with preservative (mineral oil and fish oil mixed in a 1:1 volume ratio), and use small hemp fiber mortar to fill the gaps between adjacent boards. Apply preservative (linseed oil and tung oil mixed in a 1:1 volume ratio) evenly to the boards.

[0061] S2. Apply 10-20mm of protective plaster to the sheathing board and let it dry for no less than 8 hours after application.

[0062] In S2, the protective ash includes white ash, blue ash, and additives mixed in a mass ratio of 100:8:3. The additives are nano silica, hemp fiber, and linseed oil.

[0063] After the protective plaster in S3 and S2 has dried slightly, apply the plaster backing in layers. After each layer of plaster is applied, let it dry, smooth it, and compact it. The thickness of each layer of plaster backing should not exceed 50mm. When it is about 70-80% dry, use a round iron apricot-shaped paddle to pat the backing.

[0064] In S3, the mortar backing consists of lime and loess mixed in a mass ratio of 1:3.

[0065] In S3, when applying the mortar backing, the mortar backing at the eaves and ridge can be slightly thinner, while the mortar backing at the mid-section is too thick. In this case, the roof tiles can be flipped over onto the protective mortar to reduce the roof load.

[0066] After the plaster backing in S4 and S3 is completely dry, apply a layer of light gray plaster backing. Apply a layer of coarse hemp fiber ash or coarse hemp fiber ash between the plaster backing and the light gray plaster backing. The thickness of each layer of light gray plaster backing should not exceed 30mm. After each layer of light gray plaster backing is applied, it should be repeatedly rolled and compacted before applying the next layer. After each layer of light gray plaster backing is applied, apply hemp fiber to the surface before applying the next layer. When the light gray plaster backing is about 80% dry, apply hemp fiber and make a knot. During the drying process of the light gray plaster backing, it is not allowed for people to walk on it or for materials to be piled up.

[0067] In S4, the bluish-gray backing consists of a mixture of lime, bluish-gray, and additives in a mass ratio of 100:8:3. The additives are wood fiber particles, bamboo fiber, and linseed oil. The surface of the bluish-gray backing should be free from popping, cracking, hollowing, water accumulation, efflorescence, and freezing. The surface should not be cracked, and there should be no roughness such as hemp fiber clumps, exposed hemp fibers, fuzzing, blistering, or watermarks. The slurry application and rolling must be firm and not too soft or loose.

[0068] In S4, the process of "sticking hemp and making 'guaizi'" involves using a wooden stick with a semi-circular tip to create several shallow circular indentations on the bluish-gray backing. Five indentations arranged in a plum blossom shape form a group of 'guaizi,' and hemp is stuck between each group. In some buildings, it is permissible to make 'guaizi' without sticking hemp.

[0069] Newly applied plaster and lime mortar backings should be covered promptly in case of rain to prevent water erosion. The surface of the ladder (rope ladder) used for backing application should be free of sharp objects such as nails that could scratch the backing.

[0070] S5. After removing the loose particles on the bluish-gray back, apply an interface agent. After drying, apply a nano-composite waterproof coating in the same direction. After drying, apply a second coat of nano-composite waterproof coating in a direction perpendicular to the previous one. The amount of nano-composite waterproof coating used is 1.2 kg / m². Allow it to cure naturally for 48 hours to obtain a nano-composite waterproof layer.

[0071] S6. Apply a 1mm layer of flame-retardant coating evenly to the nano-waterproof layer obtained in S5. The application direction is the same as the direction of the second coat of nano-composite waterproof coating. After the flame-retardant coating layer dries, apply a 2mm layer of flame-retardant coating in a direction perpendicular to the flame-retardant coating layer. After drying and curing at room temperature, a flame-retardant layer is obtained.

[0072] S7. Apply mortar to the ridge, lay battens and tiles on the fire-retardant layer, connect the mounting holes in the center of the tiles to the corrosion-resistant steel wires on the battens, connect the tiles to each other with mounting blocks and mounting grooves, set anti-fall blocks on the roof at the bottom of the tiles, and after all the tiles are laid, pinch the joints and fill them tightly.

[0073] In S7, the shoulder plastering involves tying a horizontal guideline on the ridge line where the two slopes intersect. The bottom of the ridge is then plastered along this line, with the plastering height being straight with the horizontal guideline and the plastering width being 300-500mm. The horizontal guideline is vertically positioned on the plaster back of the front and back slopes on both sides.

[0074] Example 2

[0075] like Figure 3 As shown in Embodiment 1, a plurality of mounting blocks 2 are provided on one side of the top of the tile 1, and a plurality of mounting grooves 3 are provided on one side of the bottom of the tile 1. The mounting blocks 2 and the mounting grooves 3 are connected in cooperation. The bottom of the mounting groove 3 is provided with a water passage hole 4. The mounting grooves 3 are connected by the mounting blocks 2, so that while adjacent tiles 1 are laid, the tiles 1 are prevented from slipping off the roof on a steep slope, thus increasing the safety of the tile 1 after installation. The water passage hole 4 is provided to prevent rainwater from accumulating in the mounting groove 3.

[0076] like Figure 2 As shown, according to the spacing of the batten strips 7 on the roof, when the tiles 1 are laid on the fire-retardant layer, the mounting hole 5 in the center of the tile 1 connects to the corrosion-resistant steel wire 8 on the batten strips 7. The tiles 1 are connected to each other via mounting blocks 2 and mounting grooves 3. An anti-fall block 6 is installed on the roof at the bottom of the tile 1. The height of the anti-fall block 6 is lower than the horizontal height of the concave surface of the tile 1, ensuring smooth drainage while preventing the tile 1 from slipping.

[0077] like Figure 4 and Figure 5 As shown, a corrosion-resistant steel wire 8 connects adjacent battens 7, and a corrosion-resistant steel wire 8 spans the ridge. The battens 7 on both sides of the ridge are connected to the corrosion-resistant steel wire 8. The corrosion-resistant steel wire 8 then passes through the mounting holes 5 to connect the battens 7 to the roof tiles 1, increasing the tightness of the connection between the roof tiles 1 and the battens 7, reducing gaps between them, improving waterproofing performance, and preventing the roof tiles 1 from slipping off the roof.

[0078] Example 3

[0079] The preparation method of the nanocomposite waterproof coating in S5 in Example 1 includes the following steps:

[0080] T1. Weigh out 70 parts by weight of water-based acrylic emulsion, 1 part of nano-silane, 0.5 parts of nano-silica, 0.5 parts of nano-zinc oxide, 2 parts of nano-fluorocarbon, 1 part of dispersant, and 3 parts of plasticizer (citric acid ester).

[0081] T2. Mix the aqueous acrylic emulsion and dispersant, stir at 300 rpm / min for 8 min, add nano fluorocarbon, nano silica and nano zinc oxide in sequence, stir at 900 rpm / min for 25 min until uniformly dispersed, and grind to obtain a nanoparticle dispersion system.

[0082] At T3 and 300 rpm / min, nano-silane was slowly added to the nano-ion dispersion system in T2 and stirred until the nano-silane and the nano-ion dispersion system were mixed evenly. Plasticizer (citric acid ester) was added while stirring to obtain nano-composite waterproof coating.

[0083] Therefore, the present invention adopts a construction method for a modern traditional style wooden structure tile roof using the above steps, and uses compound additives to reduce the porosity of lime mortar and increase tensile strength, toughness and adhesion.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A construction method for a modern traditional-style wooden tile roof, characterized by: Includes the following steps, S1. Lay the roof boards impregnated with preservatives, and use small hemp fiber mortar to fill the gaps between adjacent roof boards. Inject preservatives at the tenon and mortise joints and corners of the roof boards. S2. Apply 10-20mm of protective plaster to the sheathing board and let it dry for no less than 8 hours after application. The protective plaster includes lime, ash and additives mixed in a mass ratio of 100:8:3-8. After the protective plaster in S3 and S2 has dried slightly, apply the plaster backing in layers. After each layer of plaster is applied, let it dry, smooth it, and compact it. The thickness of each layer of plaster backing should not exceed 50mm. When it is about 70-80% dry, pat the backing. After the mortar backing in S4 and S3 is completely dry, apply a layer of blue-gray backing. The thickness of each layer of blue-gray backing should not exceed 30mm. After each layer of blue-gray backing is applied, apply hemp fiber to the surface before applying the next layer. When the blue-gray backing is about 80% dry, apply hemp fiber and make a knot. The blue-gray backing includes white lime, blue-gray lime and additives mixed in a mass ratio of 100:8:3-8. S5. After removing the loose particles on the bluish-gray back in S4, apply an interface agent. After drying, brush on the nano-composite waterproof coating in the same direction. After drying again, brush on the second coat of nano-composite waterproof coating in a direction perpendicular to the first coat. Allow to cure naturally for 24-48 hours to obtain the nano-composite waterproof layer. The nano-composite waterproof coating includes one or more of the following: water-based acrylic emulsion, nano-silane, nano-silica, nano-zinc oxide, nano-fluorocarbon, dispersant, and plasticizer. The dosage of the nano-composite waterproof coating is 0.6-1.5 kg / m². S6. Apply a flame-retardant coating base layer evenly to the nano-waterproof layer obtained in S5. The application direction is the same as the direction of the second coat of the nano-composite waterproof coating. After the flame-retardant coating base layer dries, apply the flame-retardant coating top layer in a direction perpendicular to the flame-retardant coating base layer. After drying and curing, the flame-retardant layer is obtained. S7. Apply mortar to the ridge, lay battens and tiles on the fire-retardant layer, connect the mounting holes in the center of the tiles to the corrosion-resistant steel wires on the battens, connect the tiles to each other with mounting blocks and mounting grooves, set anti-fall blocks on the roof at the bottom of the tiles, after all the tiles are laid, pinch the joints and fill them tightly; there are several mounting blocks on the top side of the tiles and several mounting grooves on the bottom side of the tiles, and the mounting blocks and mounting grooves are connected together. The additives include one or more of the following: nano silica, hemp fiber, polypropylene fiber, wood fiber particles, bamboo fiber, wheat straw, cellulose ether, and linseed oil; The preparation method of nanocomposite waterproof coating includes the following steps: T1. Weigh out 70 parts by weight of water-based acrylic emulsion, 1 part of nano-silane, 0.5 parts of nano-silica, 0.5 parts of nano-zinc oxide, 2 parts of nano-fluorocarbon, 1 part of dispersant, and 3 parts of plasticizer. T2. Mix the aqueous acrylic emulsion and dispersant, stir at 300 rpm / min for 8 min, add nano fluorocarbon, nano silica and nano zinc oxide in sequence, stir at 900 rpm / min for 25 min until uniformly dispersed, and grind to obtain a nanoparticle dispersion system. At T3 and 300 rpm / min, nano-silane was slowly added to the nano-ion dispersion system in T2 and stirred until the nano-silane and nano-ion dispersion system were evenly mixed. Plasticizer was then added while stirring to obtain a nano-composite waterproof coating.

2. The construction method for a modern traditional style wooden tile roof according to claim 1, characterized in that: In S1, the preservatives include one or more of fish oil, linseed oil, tung oil, and mineral oil.

3. The construction method for a modern traditional style wooden tile roof according to claim 1, characterized in that: In S3, the mortar backing consists of lime and loess mixed in a mass ratio of 1:

3.

4. The construction method for a modern traditional style wooden tile roof according to claim 1, characterized in that: In S4, the process of sticking hemp and making "guts" involves using a wooden stick with a semi-circular tip to make several shallow circular indentations on the bluish-gray back. Every five in a plum blossom shape form a group of "guts," and hemp must be stuck between each group of "guts." 5. The construction method for a modern traditional style wooden tile roof according to claim 1, characterized in that: In S7, the shoulder plastering involves tying a horizontal guideline on the ridge line where the two slopes intersect. The bottom of the ridge is then plastered along this line, with the plastering height being straight with the horizontal guideline and the plastering width being 300-500mm. The horizontal guideline is vertically positioned on the plaster back of the front and back slopes on both sides.

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