Therma-Flect Roof Board – Calculations
| Winter Condensation Risk Analysis (no account taken of thermal bridges) TO BS5250 |
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| Internal RH 65.0% External RH 95.0% |
NB Calculations are freely available from YBS: 01909 721 662 | |||
| Interface Temp (C) | Dewpoint Temp. (C) | Vapour Pressure (kPa) | Saturated V.P. (kPa) | |
| 1 - Outside surface resistance | 5.0 | 4.3 | 0.83 | 0.87 |
| 2 - Tiling | 5.1 | 4.3 | 0.83 | 0.88 |
| 3 - Tile & Counter Battens | 5.1 | 4.8 | 0.86 | 0.88 |
| 4 - T-F Roof Board Foil Bubble | 5.4 | 4.8 | 0.86 | 0.89 |
| 5 - T-F Roof Board PUR GOLD | 6.0 | 4.8 | 0.86 | 0.93 |
| 6 - Cavity | 14.1 | 8.4 | 1.10 | 1.61 |
| 7 - Gyproc Wallboard | 14.7 | 8.4 | 1.10 | 1.67 |
| 8 - Inside Surface Resistance | 14.8 15.0 |
8.5 8.5 |
1.11 1.11 |
1.69 1.70 |
Therma-Flect Roof Board – U-Value Calculation
Contact YBS Insulation Ttechnical for further information
| Construction | ||||
| Thickness (mm) | Thermal Conductivity (W/mK) | Thermal Resistance |
Pitch & Bridge Details |
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| Outside surface resistance | – | – | 0.040 | – |
| Tiling | 10.00 | – | 0.012 | – |
| Tile & Counter Battens | 50.00 | – | 0.454 | bridged by 11.1% Timber (50.0mm) |
| T-F Roof Board Foil Bubble | 4.00 | – | 0.125 | – |
| T-F Roof Board PUR GOLD | 115.00 | 0.023 | 5.000 | bridged by 9.5% Timber (100.0mm) |
| Cavity | 35.00 | – | 0.350 | bridged by 9.5% Timber (50.0mm) |
| Gyproc Wallboard | 12.50 | 0.210 | 0.060 | – |
| Inside Surface Resistance | – | – | 0.100 | – |
| U-value, Combined method 0.2W/m:²K (lower limit = 4.108m2K/W, upper limit = 5.190m:²K/W) |
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| Construction Type | |
| Element | Pitched roof ceiling at rafter line |
| Exposure | normal |
| Internal surface emissivity | high |
| External surface emissivity | high |
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| achieves 0.2 U-Value through roof |
Fully insulates and waterproofs in one application |
| No felt or vapour barrier required | Meets: Part L1 & L2 andPart J |
| Major labour savings... Boards can be pre-cut to fit |
Meets NHBC standards |
| High performance | No special fixings required |
FULLY PATENTED/CERTIFIED
Therma-Flect Roofboard: 050/98
When installing Therma-flect Roof Board below tiling, moisture escapes through the horizontal open laps. It should therefore be considered for design purposes as a permeable membrane, allowing moisture to escape. Condensation risk calculations to BS 5250 are available from the YBS Technical Department
Due care must be taken that the Therma- Flect Roof Board* does not obstruct the flow of air at any ventilation opening.
