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As Qualified Carpenters & Joiners we have the knowledge, expertise, experience and commercial tools to do a professional Bespoke Joinery service

Contact Robert 07544 030486 for Assistance and Guidance

Or if you prefer, email me at robert@coulsy.co.uk

Fully Qualified City and Guilds Advanced Craft Carpenter & Joiner since 1988 

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u-values-and-building-regulations-for-insulating-your-home

in Building And Construction

Building Regulations, Standards and U-Values

The lower the U-Value the more insulation there is in a building element, (e.g a floor, ceiling or wall). Therefore the less heat loss.
Consequently, the higher the U-Value, the more heat loss you have in the home.

U-Values are important because there are certain standards according to the Building Regulations and Standards depending on location.

For example, Scotland buildings will need a lower U-Value due to the colder weather than England. Wales can get away with having a higher U-Value than England and Scotland because it is typically less cold.

u-values demonstration

 

The tables below show the suggested U-values in England, Wales and Scotland. Note the distinction between the domestic and non-domestic columns.

England

Domestic Non-domestic
New Build Existing Buildings New Build Existing Buildings
Best Starting Point (Fabric Only) Extension Refurbishment Best Starting Point (Fabric Only) Extension Refurbishment
Wall 0.16 0.28 0.30 / 0.55 * 0.22 0.28 0.30 / 0.55 *
Floor 0.11 0.22 0.25 0.18 0.22 0.25
Pitched Roof – Ceiling Level 0.11 0.16 0.16 0.14 0.16 0.16
Pitched Roof – Rafter Level 0.11 0.18 0.18 0.14 0.18 0.18
Flat Roof 0.11 0.18 0.18 0.14 0.18 0.18

* A U-value of 0.55 W/m²·K is used for cavity insulation and 0.30 W/m²·K for internal or external wall insulation.

Wales

Domestic Non-domestic
New Build Existing Buildings New Build Existing Buildings
Best Starting Point (Fabric Only) Extension Refurbishment Best Starting Point (Fabric Only) Extension (Domestic in Character) Extension (Other Buildings) Refurbishment
Wall 0.16 0.21 0.30 / 0.55 * 0.22 0.21 0.26 0.30 / 0.55 *
Floor 0.11 0.18 0.25 0.18 0.18 0.22 0.25
Pitched Roof – Ceiling Level 0.11 0.15 0.16 0.14 0.15 0.15 0.16
Pitched Roof – Rafter Level 0.11 0.15 0.18 0.14 0.15 0.18 0.18
Flat Roof 0.11 0.15 0.18 0.14 0.15 0.18 0.18

* A U-value of 0.55 W/m²·K is used for cavity insulation and 0.30 W/m²·K for internal or external wall insulation.

Scotland

Domestic Non-domestic
New Build Existing Buildings New Build Existing Buildings
Best Starting Point (Fabric Only) Extension & Refurbishment * Conversion of Heated Buildings Best Starting Point (Fabric Only) Refurbishment, Extension & Conversion of Unheated Buildings Conversion of Heated Buildings
A B
Wall 0.15 0.17 0.22 0.30 0.18 0.25 0.30
Floor 0.13 0.15 0.18 0.25 0.15 0.20 0.25
Pitched Roof – Ceiling Level 0.10 0.11 0.15 0.25 0.14 0.15 0.25
Pitched Roof – Rafter Level 0.10 0.13 0.18 0.25 0.14 0.15 0.25
Flat Roof 0.10 0.13 0.18 0.25 0.14 0.15 0.25

* Column A is for extensions where the existing dwelling’s walls and roof U-values are worse than 0.70 W/m²·K in the walls and worse than 0.25 W/m²·K in the ceiling. Column B is for other extensions, upgraded existing thermal elements, non-exempt conservatories and conversion of unheated buildings.

For more information on Roofing Insulation, or if you would like to make an order – please email info@coulsy.co.uk or call 07544 030486

 

 Resources

Rafter Lengths

in Carpentry and Joinery

Rafter Lengths

Have you ever wanted to know how to work out the rafter length for your roof?

Here are two ways you can do this by applying a little bit of maths depending on what facts you already know.

Method 1  –  You know both the rise and run

The simplest way is to use Pythagoras’ Theorem which we have already written about here. Mathematically the rafter length, c, is found using the following equation:

1409736816Pythagorad1.jpg
1409736999Rafter length.jpg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For example. Rise = 1.8m, Run = 2.4m

Rafter length  =  √ [ (2.4)2 + (1.8)2 ]  =  3.0m

The eagle-eyed will have spoted this is another example of a 3-4-5 triangle.

Method 2  –  You know the roof pitch, θ, and the rise or the run.

Using a bit of trigonometry you can find the rafter length using the following equations.

Rafter length            =         Run ÷ cos θ       =         Rise ÷ sin θ

For example. Run = 2.4m, roof pitch = 45°

Rafter length  =  2.4 ÷ cos(45°)  =  3.39m to 2 d.p.

Any modern mobile phone will be able to perform these calculations.

There is a useful table below for your convenience.

Just multiply the rise or run by the appropriate rafter length factor corresponding to your roof pitch.

For example, if your roof pitch is 30ﹾ and your run is 2.4m then reading from the table the rafter length factor is 1.15. Multiply this factor by your run which gives your rafter length. If you want to add on a rafter foot (overhang) add this to your rafter length.

(   2.4     x     1.15  )     +     0.45     =     3.21 metre

                Run                Factor              Overhang           Rafter length

Roof Pitch
10ﹾ 15ﹾ 20ﹾ 25ﹾ 30ﹾ 35ﹾ 40ﹾ 45ﹾ 50ﹾ 55ﹾ 60ﹾ
Rafter factor for rise (to 2 d.p.) 5.76 3.86 2.92 2.37 2.00 1.74 1.56 1.41 1.31 1.22 1.15
Rafter factor for run (to 2 d.p.) 1.02 1.04 1.06 1.10 1.15 1.22 1.31 1.41 1.56 1.74 2.00

Building Regulations

in Building And Construction
  • Part A – Structure
  • Part B – Fire Safety
  • Part C – Site preparation and resistance to contaminants and moisture
  • Part D – Toxic Substances
  • Part E – Resistance to the passage of sound
  • Part F – Ventilation
  • Part G – Hygiene
  • Part H – Waste Disposal
  • Part J – Combustion appliances and fuel storage systems
  • Part K – Protection from falling, collision and impact
  • Part L – Conservation of fuel and power
  • Part M – Access to facilities and buildings
  • Part N – Glazing
  • Part P – Electrical Safety
  • Part Q – Security in Dwellings
  • Part R – High Speed Electronic Communications Networks
  • Part 7 – Material and Workmanship

U-values are a measure of thermal transmittance and express the rate of heat transfer through any element of your building, such as the wall, roof, window or indeed any structural component. The higher the figure, the worse the thermal insulation quality. So aim to keep your U-values low.

Because the construction of these elements can vary so much depending on your design and choice of materials, the U-values vary too and hence they need to be calculated specifically for each element. The units used to express U-values are watts per m² Kelvin (W/m²K). This means that if a wall, for example, had a U-value of 1.0 W/m²K, for every degree of temperature difference between the air on the surface inside the wall and the air on the surface outside, 1 watt of heat would pass through any m².

In addition to the Building Regulations, you may be asked to comply with other guidelines including CFSH (Code for Sustainable Homes), SAP (Standard Assessment Procedures), SBEM calculations (Simplified Building Energy Model) and EPC (Energy Performance Certificates).

Garden Retreat

in Inspiration / News

Garden Retreat

Garden Offices, Garden Rooms and Garden Studios

As a joinery contractor we are well placed to offer this service of building Garden Offices, Garden Rooms, Garden Studios and Granny Annexes.

Garden Offices, Garden Rooms, Garden Studios, Granny Annexes built Yorkshire, Lancashire

Garden Offices, Garden Rooms, Garden Studios, Granny Annexes built Yorkshire, Lancashire

 

 

Door Hinge Jig Calculator

in Woodworking

Use this simple hinge jig calculator to work out quickly the internal size you need to make your jig so you can use a router to machine your hinge cut outs.

Premium hinge leaf measurements:

3″ the leaf is generally 76mm x 19mm | 4″ the leaf is generally 102mm x 30mm

Enter Hinge Leaf Length mm
Enter Hinge Leaf Width mm
Enter Router Guide Bush Diameter mm
Enter Router Cutter Diameter mm
Collet – Cutter Difference mm
Collet – Cutter Difference ( Half ) mm
Hinge Jig Opening Length – Internal dimension for router guide to follow mm
Hinge Jig Opening Width – Internal dimension for router guide to follow mm

Handy Guides

Or

PDF Jig making collar and cutter guide

External Guidance

FD30 FD60 Hardware Installation : Forza Doors

FD30 Fitting Instructions : Jeldwen Doors