Residential Building

  • Cavity Wall Insulation
  • Underdeck Insulation
  • Internal Wall Insulation

Cavity Wall Insulation

Cavity Wall Insulation is one of the safest practices for wall insulation application. Twiga Insul boards are placed in between the cavity of the wall leaves. The insulation remains isolated from external and internal environment of the building.

Twiga Insul boards can be fixed to the internal side of external leaf by means of washer and screw and tie wires and then covered with internal leaf of wall. For vented or un-vented air gap between the insulation and internal leaf, Twiga Insul boards laminated with vapor barrier (FSK or WMP VR) is recommended.

With 50 mm thick Twiga Insul boards of density from 24-48 Kg/m3, excellent thermal resistance value (R-Value) ranging from 1.52 to 1.67 sq.mK/W and U-value <= 0.44 (ECBC compliant) can be achieved.

Specification:

A standard cavity wall insulation system should be comprised of a 230 mm brick wall, one layer of 50 mm thick glass wool slab having 24 Kg/m3 density, a 20mm air gap and finally 115 mm thick brick wall. The overall Thermal transmittance or U-value should be less than 0.44 W/sq.m.K to conform ECBC-2007’s requirement. The insulation should conform to non-combustibility, Class-P (not easily ignitable), Class 1(surface spread of flame NIL), and Class ‘O’ rating as per BS 476 standards.

Installation

  • The inner leaf of the wall construction should be cleaned of mortar protrusions before fitting glasswool slabs between each horizontal run of wall ties.
  • The mortar dropping should be cleaned from top of the insulation slabs before placing next row in position.
  • The mortar dropping should be cleaned from top of the insulation slabs before placing next row in position.
  • An air gap of 20 mm should be left between insulation and external wall leaf. This ensure normal drainage and ventilation of the cavities.
  • Joints between the insulation slabs should be close butted with all vertical joints staggered.
  • Insulation slabs are held back against the face of the inner leaf by drip prong of wall ties, special clips or adhesive.
  • During construction of the external wall the insulation should be temporarily covered with polyethylene sheet so that dirt, water cannot go inside the insulation
Composition
(Outside to inside)
Thickness,in mm Thermal Resistance,R in sq.m.K/W Thermal TransmittanceU in W/sq.m.K U=1/R-Total ECBC Compliance
Outer Air film - 0.044 Sandstone plaster 12.5 0.014 Common Brick 230 0.32 Air gap 25 0.15 Glasswool insulation (24 Kg/m3 density) 50 1.52 Common Brick 115 0.16 Inside Air film - 0.12
0.429
U(maximum)=0.44 W/sq.m.K Hence the system comply ECBC as the calculated U value is less than ECBC’specified U value
Total Thermal Resistance R-Total
2.328
Note : Other than Twiga Insul boards and sandstone R values, all values are derived from ISHRAE Handbook-Table no. 8, page no. 1.12-1.15.
For Sandstone plaster value taken from ECBC2007
Refer Twiga Insul brochure for R-value of Glasswool insulation.

Under-deck insulation

In Under-deck insulation system, Twiga Insul board is installed against the true ceiling to reduce heat gain or loss through it. Under-deck insulation system with Twiga Insul is one of the most cost effective methods to insulate building envelope.

Vapour barrier like Aluminum based FSK or Polypropylene based WMP-VR should be factory-applied on Twiga Insul and placed towards bottom side of the system. Under-deck insulation with Twiga Insul is easy to apply, cost effective and meets ECBC requirements.

Twiga Insul boards can be applied against true ceiling with the help of screws with GI washer or small angle-pieces and G.I tie wires.

With 50-75 mm thick Twiga Insul boards of density 24-48 Kg/m3; thermal resistance value (R-Value) of 1.52 to 2.5 sq.mK/W and U-value <= 0.409 (ECBC compliant) can be achieved.

Specification

Under-deck insulation should be done with glasswool having 48 Kg/m3 density and 70 mm thickness suitably installed so that the overall Thermal transmittance or U-value should be less than 0.409 W/sq.m.K to conform ECBC-2007’s requirement. The insulation should conform to non-combustibility, Class-P(not easily ignitable), Class 1(surface spread of flame NIL), and Class ‘O’ rating as per BS 476 standards. Please refer the installation guideline as mentioned below

Installation

  • The ceiling surface is thoroughly cleaned.
  • Fix soffit / clamp to ceiling by means of rawl plug/ dash fasteners.
  • Fix Z or C shaped GI channel runners or aluminium ones along the length of the room at 600mm spacing in one direction to the ceiling by rawl plugs/dash fasteners.
  • Apply any suitable adhesive to the ceiling and place slabs of Twiga Fiberglass insulation in between by spot sticking method.
  • Hold the insulation slab in position by 22 SWG GI lacing wire placed diagonally.
  • Apply 12 mm Gypboard or equivalent plaster board to cover up the insulation.

Energy Code Compliance : Under-deck insulation

Composition
(Outside to inside)
Thickness,in mm Thermal Resistance,R in sq.m.K/W Thermal TransmittanceU in W/sq.m.K U=1/R-Total ECBC Compliance
Outer Air film - 0.044 RCC 150 0.084 Glasswool insulation (48 Kg/m3 density) 70 2.33 Gyp board 12.5 0.08 Inside Air film - 0.16
0.37
U(maximum)=0.409 W/sq.m.K Hence the system comply ECBC as the calculated U value is less than ECBC’specified U value
Total Thermal Resistance R-Total
2.328
Note : Other than Glasswool insulation and Sandstone all values are derived from ISHRAE Handbook-Table no. 8, page no. 1.12-1.15.
For Sandstone plaster value taken from ECBC2007
Refer Twiga Insul brochure for R-value of Glasswool insulation.

Dry Wall Insulation

Dry Wall Insulation helps attain acoustic privacy and fire rating. Twiga Insul slabs are to be placed in the cavities of the grid structure for partition wall. Both side of the grid is then covered with single or multiple layers of Gypsum or fiber cement boards. When it is applied for Prefab structures the construction helps to provide thermal efficiency of the building, too.

With 25mm, 50mm, 75 mm, 100mm thick Twiga Insul slabs of density 24-48 Kg/m3,, STC value of 34 – 67 dB and thermal resistance (R-value) of 0.75 to 3.33 sq.mK/W can be obtained.

Energy Code Compliance : Internal solid wall insulation

Specification

The solid wall made out of 200 mm thick AAC blocks, should be internally insulate with 50 mm thick and 24 Kg/m3 glasswool and suitably covered with gyp-board or equivalent product. The overall Thermal transmittance or U-value should be less than 0.44 W/sq.m.K to conform ECBC-2007’s requirement. The insulation should conform to non-combustibility, Class-P(not easily ignitable), Class 1(surface spread of flame NIL), and Class ‘O’ rating as per BS 476 standards. Please refer the installation guideline as mentioned below :

Installation

  • Batten out surface of wall to suit width of insulation slabs.
  • Insulation slabs should be fixed snugly between battens without gaps.
  • Depending upon humidity a layer of pre laminated Vapour barrier can be used(optional) on insulation. The joints of the vapour barrier should be sealed with self adhesive Aluminum tape.
  • Fix expanded metal galvanized chicken mesh or plastic netting over the insulation as a key for rendering, fixing it into vertical batten with staples or flat head nails.
  • Final finish can be done with gyp-board or equivalent board.
Composition
(Outside to inside)
Thickness,in mm Thermal Resistance,R in sq.m.K/W Thermal TransmittanceU in W/sq.m.K U=1/R-Total ECBC Compliance
Outer Air film - 0.044 Sand Cement plaster 12.5 0.017 AAC block 200 1.25 Glasswool insulation (24 Kg/m3 density) 50 1.52 Gyp board 12.5 0.08 Inside Air film - 0.12
0.329
U(maximum)=0.44 W/sq.m.K Hence the system comply ECBC as the calculated U value is less than ECBC’specified U value
Total Thermal Resistance R-Total
3.03
Note : Other than Twiga Insul boards and sandstone R values, all values are derived from ISHRAE Handbook-Table no. 8, page no. 1.12-1.15.
Refer Twiga Insul brochure for R-value of Glasswool insulation.