Construction assembly of skim coated prefabricated elements and jointing material, a kit therefor, and method of assembling the same

• US 20040237436A1
• Filed: 07/07/2004
• Published: 12/02/2004
• Est. Priority Date: 06/30/1995
• Status: Active Grant

• Current Assignee: Continental Building Products Operating Company, Llc (Compagnie De Saint-Gobain S.A.)
• Original Assignee: Lafarge Platres (Holcim Limited)
• Inventors: Leclercq, Claude, Bilodeau, Sylvie, Boucher, Roland, Colbert, Elizabeth A., Zuber, Francois, Gagne, Pierre, Bourne-Chastel, Pascal
• Granted Patent: US 8,151,532 B2
• Time in Patent Office: Days
• US Class Current: 52/393
• CPC Class Codes: B32B 13/08 of paper or cardboard
• CPC Class Codes: C04B 26/02 Macromolecular compounds
• CPC Class Codes: C04B 26/04 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C04B 41/4857 Other macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C04B 41/63 Macromolecular compounds
• CPC Class Codes: E04F 13/02 of plastic materials hardening after applying, e.g. plaster surface treatment in painting technique B44D; inorganic or bituminous masses C04B; organic plastics C08L ; implements for applying plasticised materials E04F21/02
• CPC Class Codes: E04F 13/04 Bases for plaster sub-ceilings with plaster-carrying means E04B9/06
• CPC Class Codes: E04F 13/047 Plaster carrying meshes
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/31906 Ester, halide or nitrile of addition polymer
• CPC Class Codes: Y10T 428/31993 Of paper
• CPC Class Codes: Y10T 428/31996 Next to layer of metal salt [e.g., plasterboard, etc.]

Abstract

A construction assembly for interior works including prefabricated elements, wherein the prefabricated elements include a coating layer formed of at least one skim coat deposited on the prefabricated elements by a coating device; and at least one jointing material, e.g. a sealing coat, joint coat and/or joint pointing coat, which joints adjacent said prefabricated elements to form a substantially plane outer surface.

Claims

1. A construction assembly for interior works, comprising:

(1) skim coated prefabricated elements comprising prefabricated elements having at least one skim coat deposited on said prefabricated elements;

(2) at least one jointing material jointing said skim coated prefabricated elements to form a substantially plane outer surface comprising a visible surface of at least one joint and a visible surface of the skim coated prefabricated elements, wherein said at least one jointing material and said at least one skim coat comprise a mineral filler, a binder and water; and

wherein the compositions of said at least one jointing material and said at least one skim coat are adapted to each other, whereby said at least one jointing material and said at least one skim coat form, both in a dry state, a substantially homogeneous outer surface having, over substantially an entire visible surface of said at least one jointing material and substantially an entire visible surface of said at least one skim coat, at least one parameter selected from the group consisting of coloration, reflectance factor and surface water absorbability that is substantially homogeneous over said outer surface; and

whereby said outer surface is ready to be decorated.

2. The construction assembly according to claim 1, wherein said at least one jointing material and said at least one skim coat exhibit substantially the same surface water absorbability.

3. The construction assembly according to claim 1, wherein said at least one jointing material and said at least one skim coat have substantially the same solids formulation, said at least one skim coat when applied having a solids content lower than said at least one jointing material when applied.

4. The construction assembly according to claim 3, wherein said at least one skim coat comprises about 15 to 40% more water than initially present in said at least one jointing material.

5. The construction assembly according to claim 1, wherein said at least one skim coat is applied to said prefabricated elements with a coating roll.

6. The construction assembly according to claim 1, wherein said at least one skim coat has a thickness between about 0.01 mm and about 2 mm.

7. The construction assembly according to claim 1, wherein said at least one jointing material is at least a joint-pointing coat, wherein said joint-pointing coat and said at least one skim coat have the following composition by weight:

40 to 70% of a mineral filler;

1 to 10% of hydrophobic surface perlite;

0.1 to 10% of a binder;

0.1 to 10% of a handling agent;

0.1 to 5% of a slipping agent;

0.1 to 20% of another silicate derivative as an additional slipping agent; and

water with optional conventional additives up to 100%.

8. The construction assembly according to claim 1, wherein the surface water absorption of each of said at least one jointing material and said at least one skim coat is not less than 60 minutes such as measured by the water drop test, at 23°

C.

9. The construction assembly according to claim 1, wherein the reflectance factor of the overall surface, including that of a visible face of said at least one jointing material in a dry state, is in the range of 70% to 80% for a wavelength of 475 nm.

10. The construction assembly according to claim 1, wherein the discoloration or coloration of the overall surface, including that of a visible face of said at least one jointing material in a dry state, has a color deviation (delta E*) at most equal to 3 after exposure for 72 hours to a source of UV radiation arranged at 15 cm from the surface and having a wavelength at least equal to 290 nm.

45. The construction assembly according to claim 4, wherein said at least one skim coat comprises about 25% more water than initially present in said at least one jointing material.

46. The construction assembly according to claim 6, wherein said at least one skim coat has a thickness between about 0.2 and about 1 mm.

47. The construction assembly according to claim 7, wherein the mineral filler is calcium carbonate, the binder is either polyvinyl acetate or acrylic acid ester in aqueous solution, the handling agent is a cellulosic ether, the slipping agent is clay, and the additional slipping agent is either talc or mica.

48. The construction assembly according to claim 9, wherein the reflectance factor of the overall surface is in the range of 72% to 76% for a wavelength of 475 nm.

60. The construction assembly of claim 1, wherein said prefabricated elements are plaster boards, each of which plaster boards comprises a plaster body and at least one sheet of lining paper, wherein the lining paper comprises an upper layer or web comprising cellulose fibers and/or a mineral filler.

61. The construction assembly of claim 60, wherein the cellulose fibers are white and the mineral filler is of a light color.

68. The construction assembly of claim 1, wherein, when said at least one jointing material and said at least one skim coat are both in a dry state, said at least one of the parameters differs by no more than 10% at different parts of the outer surface, so that at least 90% homogeneity is achieved.

72. The construction assembly of claim 1, wherein said at least one skim coat comprises a mineral filler of having a grain size of between 5 and 35 μ

m.

73. The construction assembly of claim 1, wherein said at least one skim coat comprises, on a wet basis, a mineral filler in an amount of between 40% and 70% of the total weight.

74. The construction assembly of claim 1, wherein said at least one skim coat comprises, on a wet basis, an organic binder dispersible in an aqueous phase, which organic binder represents between 1% and 20% of the total weight.

84. The construction assembly of claim 1, wherein said joint material comprises, by weight based on the total weight of the joint material:

between 50% and 85% of at least one mineral filler of white color, having a grain size of between 5 and 35 μ

m;

at least one organic binder dispersible in an aqueous phase, which organic binder represents between 1% and 20%;

at least one handling agent;

water up to 100%.

85. The construction assembly of claim 84, wherein said joint material further comprises a handling agent which is a water-retaining and thickening agent.

86. The construction assembly of claim 84, wherein said joint material further comprises a slipping agent which is a clay.

11. A construction assembly for interior works, comprising:

(1) skim coated prefabricated elements comprising prefabricated elements having a coating layer formed of at least one skim coat deposited on said prefabricated elements, said at least one skim layer having a thickness between about 0.01 mm and about 2 mm;

(2) at least one jointing material jointing said skim coated prefabricated elements to form a substantially plane outer surface comprising a visible surface of at least one joint and a visible surface of the skim coated prefabricated elements;

wherein said at least one jointing material and said at least one skim coat comprise a mineral filler, a binder and water;

wherein said at least one jointing material and said at least one skim coat have substantially the same solids formulation, said at least one skim coat when applied having a solids content lower than said at least one jointing material when applied, whereby said at least one jointing material and said at least one skim coat form, both in a dry state, a substantially homogeneous outer surface having, over substantially an entire visible surface of said at least one jointing material and substantially an entire visible surface of said at least one skim coat, at least one parameter selected from the group consisting of coloration, reflectance factor and surface water absorbability that is substantially homogeneous over said outer surface; and

whereby said outer surface is ready to be decorated.

12. The construction assembly according to claim 11, wherein said at least one skim coat comprises about 15 to 40% more water than initially present in said at least one jointing material.

13. The construction assembly according to claim 11, wherein said at least one jointing material and said at least one skim coat exhibit substantially the same surface water absorbability.

14. The construction assembly according to claim 11, wherein said at least one jointing material and said at least one skim coat have the following composition, by weight:

40 to 70% of a mineral filler;

1 to 10% of hydrophobic surface perlite;

0.1 to 10% of a binder;

0.1 to 10% of a handling agent;

0.1 to 5% of a slipping agent;

0.1 to 20% of another silicate derivative as an additional slipping agent; and

water with optional conventional additives up to 100%.

15. The construction assembly according to claim 11, wherein the surface water absorption of each of said at least one jointing material and said at least one skim coat is not less than 60 minutes such as measured by the water drop test, at 23°

C.

16. The construction assembly according to claim 11, wherein the reflectance factor of the overall surface, including that of a visible face of said at least one jointing material in a dry state, is in the range of 70% to 80% for a wavelength of 475 nm.

17. The construction assembly according to claim 11, wherein the discoloration or coloration of the overall surface, including that of a visible face of said at least one jointing material in a dry state, has a color deviation (delta E*) at most equal to 3 after exposure for 72 hours to a source of UV radiation arranged at 15 cm from the surface and having a wavelength at least equal to 290 nm.

49. The construction assembly according to claim 12, wherein said at least one skim coat comprises about 25% more water than initially present in said at least one jointing material.

50. The construction assembly according to claim 14, wherein the mineral filler is calcium carbonate, the binder is either polyvinyl acetate or acrylic acid ester in aqueous solution, the handling agent is a cellulosic ether, the slipping agent is clay, and the additional slipping agent is either talc or mica.

51. The construction assembly according to claim 16, wherein the reflectance factor of the overall surface is in the range of 72% to 76% for a wavelength of 475 nm.

62. The construction assembly of claim 11, wherein said prefabricated elements are plaster boards, each of which plaster boards comprises a plaster body and at least one sheet of lining paper, wherein the lining paper comprises an upper layer or web comprising cellulose fibers and/or a mineral filler.

63. The construction assembly of claim 62, wherein the cellulose fibers are white and the mineral filler is of a light color.

69. The construction assembly of claim 11, wherein, when said at least one jointing material and said at least one skim coat are both in a dry state, said at least one of the parameters differs by no more than 10% at different parts of the outer surface, so that at least 90% homogeneity is achieved.

75. The construction assembly of claim 11, wherein said at least one skim coat comprises a mineral filler of having a grain size of between 5 and 35 μ

m.

76. The construction assembly of claim 11, wherein said at least one skim coat comprises, on a wet basis, a mineral filler in an amount of between 40% and 70% of the total weight.

77. The construction assembly of claim 11, wherein said at least one skim coat comprises, on a wet basis, an organic binder dispersible in an aqueous phase, which organic binder represents between 1% and 20% of the total weight.

87. The construction assembly of claim 11, wherein said joint material comprises, by weight based on the total weight of the joint material:

between 50% and 85% of at least one mineral filler of white color, having a grain size of between 5 and 35 μ

m;

at least one organic binder dispersible in an aqueous phase, which organic binder represents between 1% and 20%;

at least one handling agent;

water up to 100%.

88. The construction assembly of claim 87, wherein said joint material further comprises a handling agent which is a water-retaining and thickening agent.

89. The construction assembly of claim 87, wherein said joint material further comprises a slipping agent which is a clay.

18. A method for the construction of interior works, comprising the following steps:

(1) assembling skim coated prefabricated elements, wherein said skim coated prefabricated elements have a coating layer formed of at least one skim coat deposited on said prefabricated elements by a coating device;

(2) jointing adjacent prefabricated elements with at least a sealing coat or joint coat to form joints;

(3) finishing said joints between adjacent said prefabricated elements with at least one jointing material, wherein said at least one jointing material is a sealing coat, joint coat or joint-pointing coat; and

thereafter

(4) drying said at least one jointing material;

wherein said at least one jointing material and said at least one skim coat comprise a mineral filler, a binder and water; and

wherein the composition of said at least one jointing material and said at least one skim coat are adapted to each other, whereby said at least one jointing material and said at least one skim coat form, both in a dry state, a substantially homogeneous outer surface having, over substantially an entire visible surface of said at least one jointing material and substantially an entire visible surface of said at least one skim coat, at least one parameter selected from the group consisting of coloration, reflectance factor and surface water absorbability that is substantially homogeneous over said outer surface; and

whereby said outer surface is ready to be decorated.

19. The method according to claim 18, wherein said at least one jointing material and said at least one skim coat exhibit substantially the same surface water absorbability.

20. The method according to claim 18, wherein said at least one jointing material and said at least one skim coat have substantially the same solids formulation, said at least one skim coat when applied having a solids content lower than said at least one jointing material.

21. The method according to claim 20, wherein said at least one skim coat, when applied, comprises about 15 to 40% more water than initially present in said at least one jointing material.

22. The method according to claim 18, wherein said at least one skim coat is applied on said prefabricated elements with a coating roll.

23. The method according to claim 18 wherein said at least one skim layer has a thickness between about 0.1 and about 2 mm.

24. The method according to claim 18, wherein said at least one jointing material is a joint-pointing coat, wherein said joint-pointing coat and said skim coat have the following composition, by weight:

40 to 70% of a mineral filler;

1 to 10% of hydrophobic surface perlite;

0.1 to 10% of a binder;

0.1 to 10% of a handling agent;

0.1 to 5% of a slipping agent;

0.1 to 20% of another silicate derivative as an additional slipping agent; and

water with optional conventional additives up to 100%.

25. The method according to claim 18, wherein the surface water absorption of each of said at least one jointing material and said at least one skim coat is not less than 60 minutes such as measured by the water drop test, at 23°

C.

26. The method according to claim 18, wherein the reflectance factor of the overall surface, including that of a visible face of said at least one jointing material in a dry state, is in the range of 70% to 80% for a wavelength of 475 nm.

27. The method according to claim 18, wherein the discoloration or coloration of the overall surface, including that of a visible face of said at least one jointing material in a dry state, has a color deviation (delta E*) at most equal to 3 after exposure for 72 hours to a source of UV radiation arranged at 15 cm from the surface and having a wavelength of at least equal to 290 nm.

52. The method according to claim 21, wherein said at least one skim coat comprises about 25% more water than initially present in said at least one jointing material.

53. The method according to claim 24, wherein the mineral filler is calcium carbonate, the binder is either polyvinyl acetate or acrylic acid ester in aqueous solution, the handling agent is a cellulosic ether, the slipping agent is clay, and the additional slipping agent is either talc or mica.

54. The method according to claim 26, wherein the reflectance factor of the overall surface is in the range of 72% to 76% for a wavelength of 475 nm.

55. The method according to claim 23 wherein said at least one skim coat has a thickness between about 0.2 and about 1 mm.

64. The method of claim 18, wherein said prefabricated elements are plaster boards, each of which plaster boards comprises a plaster body and at least one sheet of lining paper, wherein the lining paper comprises an upper layer or web comprising cellulose fibers and/or a mineral filler.

65. The method of claim 64, wherein the cellulose fibers are white and the mineral filler is of a light color.

70. The method of claim 18, wherein, when said at least one jointing material and said at least one skim coat are both in a dry state, said at least one of the parameters differs by no more than 10% at different parts of the outer surface, so that at least 90% homogeneity is achieved.

71. The kit of claim 21, wherein, when said at least one jointing material and said at least one skim coat are both in a dry state, said at least one of the parameters differs by no more than 10% at different parts of the outer surface, so that at least 90% homogeneity is achieved.

78. The method of claim 18, wherein said at least one skim coat comprises a mineral filler of having a grain size of between 5 and 35 μ

m.

79. The method of claim 18, wherein said at least one skim coat comprises, on a wet basis, a mineral filler in an amount of between 40% and 70% of the total weight.

80. The method of claim 18, wherein said at least one skim coat comprises, on a wet basis, an organic binder dispersible in an aqueous phase, which organic binder represents between 1% and 20% of the total weight.

90. The method of claim 18, wherein said joint material comprises, by weight based on the total weight of the joint material:

between 50% and 85% of at least one mineral filler of white color, having a grain size of between 5 and 35 μ

m;

at least one organic binder dispersible in an aqueous phase, which organic binder represents between 1% and 20%;

at least one handling agent;

water up to 100%.

91. The method of claim 90, wherein said joint material further comprises a handling agent which is a water-retaining and thickening agent.

92. The method of claim 90, wherein said joint material further comprises a slipping agent which is a clay.

28. A kit for the construction of interior works, comprising:

(1) at least one skim coated prefabricated element, comprising at least one prefabricated element having a coating layer formed of at least one skim coat deposited on said at least one prefabricated element by a coating device; and

(2) at least one jointing material for jointing said skim coated prefabricated element to form a substantially plane outer surface comprising a visible surface of said at least one jointing material and a visible surface of said at least one skim coated prefabricated element, wherein said at least one jointing material and said at least one skim coat comprise a mineral filler, a binder and water; and

wherein the composition of said at least one jointing material and said at least one skim coat are adapted to each other, whereby said at least one jointing material and said at least one skim coat form, both in a dry state, a substantially homogeneous outer surface having, over substantially an entire visible surface of said at least one jointing material and substantially an entire visible surface of said at least one skim coat, at least one parameter selected from the group consisting of coloration, reflectance factor and surface water absorbability that is substantially homogeneous over said outer surface; and

whereby said outer surface is ready to be decorated.

29. The kit according to claim 28, wherein said at least one jointing material and said at least one skim coat exhibit substantially the same surface water absorbability.

30. The kit according to claim 28, wherein said at least one jointing material and said at least one skim coat have substantially the same solids formulation, said at least one skim coat when applied having a solids content lower than said at least one jointing material when applied.

31. The kit according to claim 30, wherein said at least one skim coat, when applied, comprises about 15 to 40% more water than initially present in said at least one jointing material.

32. The kit according to claim 28, wherein said at least one skim coat is applied on said prefabricated elements with a coating roll.

33. The kit according to claim 28, wherein said at least one skim layer has a thickness between about 0.01 and about 2 mm.

34. The kit according to claim 28, wherein said at least one jointing material is at least a joint-pointing coat, said joint-pointing coat and said at least one skim coat have the following composition, by weight:

40 to 70% of a mineral filler;

1 to 10% of hydrophobic surface perlite;

0.1 to 10% of a binder;

0.1 to 10% of a handling agent;

0.1 to 5% of a slipping agent;

0.1 to 20% of another silicate derivative as an additional slipping agent; and

water with optional conventional additives up to 100%.

35. The kit according to claim 28, wherein the surface water absorption of each of said at least one jointing material and said at least one skim coat is not less than 60 minutes such as measured by the water drop test, at 23°

C.

36. The kit according to claim 28, wherein the reflectance factor of the overall surface, including that of a visible face of said at least one jointing material in a dry state, is in the range of 70% to 80% for a wavelength of 475 nm.

37. The kit according to claim 28, wherein the discoloration or coloration of the overall surface, including that of a visible face of said at least one jointing material in a dry state, has a color deviation (delta E*) at most equal to 3 after exposure for 72 hours to a source of UV radiation arranged at 15 cm from the surface and having a wavelength at least equal to 290 nm.

56. The kit according to claim 33, wherein said at least one skim coat has a thickness between about 0.2 and about 1 mm.

57. The kit according to claim 34, wherein the mineral filler is calcium carbonate, the binder is either polyvinyl acetate or acrylic acid ester in aqueous solution, the handling agent is a cellulosic ether, the slipping agent is clay, and the additional slipping agent is either talc or mica.

58. The kit according to claim 36, wherein the reflectance factor of the overall surface, including that of an outer face of the dried joint-pointing coat, is in the range of 72 to 76% for a wavelength of 475 nm.

66. The kit of claim 28, wherein said prefabricated elements are plaster boards, each of which plaster boards comprises a plaster body and at least one sheet of lining paper, wherein the lining paper comprises an upper layer or web comprising cellulose fibers and/or a mineral filler.

67. The kit of claim 66, wherein the cellulose fibers are white and the mineral filler is of a light color.

81. The kit of claim 28, wherein said at least one skim coat comprises a mineral filler of having a grain size of between 5 and 35 μ

m.

82. The kit of claim 28, wherein said at least one skim coat comprises, on a wet basis, a mineral filler in an amount of between 40% and 70% of the total weight.

83. The kit of claim 28, wherein said at least one skim coat comprises, on a wet basis, an organic binder dispersible in an aqueous phase, which organic binder represents between 1% and 20% of the total weight.

38. (Canceled).

39. (Canceled).

40. (Canceled).

41. (Canceled).

42. (Canceled).

43. (Canceled).

44. (Canceled).

59. (Canceled).

93. A construction assembly for interior works, comprising:

(1) skim coated prefabricated elements comprising prefabricated elements having at least one skim coat deposited on said prefabricated elements;

(2) at least one jointing material jointing said skim coated prefabricated elements to form a substantially plane outer surface comprising a visible surface of at least one joint and a visible surface of the skim coated prefabricated elements,

wherein said at least one jointing material and said at least one skim coat comprise a mineral filler, a binder and water; and

wherein said at least one jointing material and said at least one skim coat, in the dry state, each have a surface water absorbability which is at least 60 minutes such as measured by the water drop test at 23°

C. and each have a surface having a reflectance factor between 70% and 80% for a wavelength of 475 nm.

94. The construction assembly according to claim 93, wherein the reflectance factor of the overall surface is in the range of 72% to 76% for a wavelength of 475 nm.

95. The construction assembly according to claim 93, wherein said at least one skim coat has a thickness between about 0.01 mm and about 2 mm.

96. The construction assembly according to claim 93, wherein said at least one skim coat has a thickness between about 0.2 and about 1 mm.

97. A construction assembly for interior works, comprising:

(1) skim coated prefabricated elements comprising prefabricated elements having a coating layer formed of at least one skim coat deposited on said prefabricated elements, said at least one skim layer having a thickness between about 0.01 mm and about 2 mm;

(2) at least one jointing material jointing said skim coated prefabricated elements to form a substantially plane outer surface comprising a visible surface of at least one joint and a visible surface of the skim coated prefabricated elements;

wherein said at least one jointing material and said at least one skim coat comprise a mineral filler, a binder and water;

wherein said at least one jointing material and said at least one skim coat have substantially the same solids formulation; and

wherein said at least one jointing material and said at least one skim coat, in the dry state, each have a surface water absorbability which is at least 60 minutes such as measured by the water drop test at 23°

C. and each have a surface having a reflectance factor between 70% and 80% for a wavelength of 475 nm.

98. The construction assembly according to claim 97, wherein the reflectance factor of the overall surface is in the range of 72% to 76% for a wavelength of 475 nm.

99. The construction assembly according to claim 97, wherein said at least one skim coat has a thickness between about 0.2 and about 1 mm.

100. A method for the construction of interior works, comprising the following steps:

(1) assembling skim coated prefabricated elements, wherein said skim coated prefabricated elements have a coating layer formed of at least one skim coat deposited on said prefabricated elements by a coating device;

(2) jointing adjacent prefabricated elements with at least a sealing coat or joint coat to form joints;

(3) finishing said joints between adjacent said prefabricated elements with at least one jointing material, wherein said at least one jointing material is a sealing coat, joint coat or joint-pointing coat; and

thereafter

(4) drying said at least one jointing material;

wherein said at least one jointing material and said at least one skim coat comprise a mineral filler, a binder and water; and

wherein said at least one jointing material and said at least one skim coat, in the dry state, each have a surface water absorbability which is at least 60 minutes such as measured by the water drop test at 23°

C. and each have a surface having a reflectance factor between 70% and 80% for a wavelength of 475 nm.

101. The method according to claim 100, wherein the reflectance factor of the overall surface is in the range of 72% to 76% for a wavelength of 475 nm.

102. The method according to claim 100, wherein said at least one skim coat has a thickness between about 0.01 mm and about 2 mm.

103. The method according to claim 100, wherein said at least one skim coat has a thickness between about 0.2 and about 1 mm.

104. A kit for the construction of interior works, comprising:

(1) at least one skim coated prefabricated element, comprising at least one prefabricated element having a coating layer formed of at least one skim coat deposited on said at least one prefabricated element by a coating device; and

(2) at least one jointing material for jointing said skim coated prefabricated element to form a substantially plane outer surface comprising a visible surface of said at least one jointing material and a visible surface of said at least one skim coated prefabricated element;

wherein said at least one jointing material and said at least one skim coat comprise a mineral filler, a binder and water; and

wherein said at least one jointing material and said at least one skim coat, in the dry state, each have a surface water absorbability which is at least 60 minutes such as measured by the water drop test at 23°

C. and each have a surface having a reflectance factor between 70% and 80% for a wavelength of 475 nm.

105. The kit according to claim 104, wherein the reflectance factor of the overall surface is in the range of 72% to 76% for a wavelength of 475 nm.

106. The kit according to claim 104, wherein said at least one skim coat has a thickness between about 0.01 mm and about 2 mm.

107. The kit according to claim 104, wherein said at least one skim coat has a thickness between about 0.2 and about 1 mm.