home-energy-saving

Part L 2019 Regulations & U-Values Explained

Here’s some helpful explanations (hopefully) of these increasingly common terms in the world of warmer homes. We don’t get scientific on anything and broke it down as simply as possible. What they are, and what you need to do!

What Is a U-Value?

What is a k-Value?

What is an R-Value?

For Current Building Regulation U-Values Go Here:


What is a U-Value?

Also known as ‘Thermal Transmittance‘.

In short, A U-value is a measure of how effective a material (or composite of materials) is as an insulator. In the case of construction, it’s generally agreed to be the most reliable way to quickly determine how much heat will be lost through a building element, i.e. A Wall, Floor, Roof or Window. But, you likely won’t get U-Values on specific insulation products. It’s a holistic figure, taking into account many things.

The Lower the U-value the Better the Performance.

A U-value is the total of the thermal resistances (explained below) of the layers that make up an entire building element – for example, a Roof (slates, felt, joists, insulation), Wall (blocks, insulation, plaster) or Floor (concrete, sand, DPM, insulation & flooring).

It also includes adjustments for any fixings or air gaps, this is critical. As homes get warmer (more and more insulation) this is where a lot of heat is actually lost in a building. And this can be loads when it’s a badly built building. Heat takes the path of least resistance. You could have 5 ft of insulation, but with lots of cracks or gaps (installed by untrained builders), it’s pointless.

So this is why the U-Value is the benchmark for our understanding of heat loss in the Construction Industry. It kind of covers all corners. Also, this is why the Building Regulations mainly consider U-values. There’s that reason too. So we need to get them right.


What is a k-Value?

Don’t get confused by the Thermal Conductivity (k-Value). This is another similar measurement of heat loss but looks at specific materials alone. It considers the transport of energy through the material (i.e. through foam insulation, or through a concrete block, and so on). It doesn’t consider the thickness of the material. So not as useful as the U-Value, which does. But it’s great to determine the quality of an INSULATION product itself.

The lower the k-Value the better the material. This one is also called the Lambda Value!

A very good k-value for say insulation is 0.022 W/mK. Xtratherm, Kingspan and some others generally make their PIR insulation (the yellow-ish stuff with foil on both sides) to this figure. It’s as good as it gets (for what people can afford anyway). So 200mm PIR is much better than 100mm PIR. (but not twice as good, don’t ask).

Mineral wool (the fuzzy soft stuff) is usually cheaper but it’s just not as good an insulator. (it has other qualities, however; easier to install in tricky spaces, and great for damping sound). But it has a k-value of 0.044 W/mK, and as you can see it’s a lot higher than the PIR (which is a bad thing). We’ll go into the differences in another post.


What is an R-Value?

And then there’s Thermal Resistance, the R-Value. If you’re looking into insulation, maybe buying some in any of the large DIY stores, you’ll likely see a lot of R-Values printed on the packs. It’s a fairly useful measure but only focuses on the conduction of heat. Which is heat passing through the material. But heat transfers in various ways, remember physics class 101; conduction, convection and radiation.

Since U-Value considers all of these in some way, it just gives a more reliable figure overall.

The thermal resistance, or R-value, measures a material’s ability to prevent the flow of heat (hot or cold air) through a certain thickness, through 100mm insulation, 200mm of insulation for example.

The Higher The R-Value The Better The Insulation


Part L Building Regulations 2019 ‘Dwellings’: U-Values

So here they are. The new 2019 U-Values we must carefully work to for new and existing dwellings. Ideally, you will be exceeding these values where possible. The difference in cost, in comparison to the overall building project, is marginal, and potential savings in heating costs over the lifetime of the home are considerable. And the Government’s Building regulations will likely reduce these again in the, not too distant future.

Refer to our page on nZEB buildings for more info on the big changes with regards to existing buildings in particular.

New Buildings – Part L 2019
Building ElementMinimum U-Value
Ground Floor (No Underfloor Heating)0.18W/m²K
Ground Floor (Underfloor Heating)0.15W/m²K
External Walls0.18W/m²k
Flat Roof0.20W/m²K
Pitched Roof (Sloping Ceilings; Rafter Level)0.16W/m²K
Cold Roof (Ceiling Level)0.16W/m²K
Existing Buildings Part L 2019
Building ElementMinimum U-Value
Ground Floor (No Underfloor Heating)0.45W/m²K
Ground Floor (Underfloor Heating)0.15W/m²K
External Walls (Cavity)0.55W/m²K**
External Walls (Other – Not Cavity)0.35W/m²K
Flat Roof0.25W/m²K
Pitched Roof (Sloping Ceilings; Rafter Level)0.25W/m²K
Cold Roof (Ceiling Level)0.16W/m²K
External Doors, Windows, Rooflights & Curtain Walling1.40W/m²K
3D model Bespoke Home

Building a Bespoke Architectural Designed Home

Building a Bespoke Architectural Designed Home

You inevitably will ask, how long does it take to design a custom bespoke architecturally designed home?  On this home, Ceardean Architects were granted planning in 2016.  This is the time from the initial concept meeting, to construction.  There are many factors that can affect this greatly, but 2 years is a good starting point.

Preliminary design can take from 3 months to 12 months, depending on how prepared the client is, the size of the project and the complexity of the design. The Planning Authorities may differ greatly from area to area and third-party objections may affect the process.

3D model Bespoke Home

3D model Bespoke Home

Tendering, contractor interviews, and contract negotiation take time.  A number of factors come into play on the construction timeline, such as

  • the Size of the project.
  • The complexity of the footprint and the materials to be used.
  • Weather can be a factor but today we can track weather and record the down days.
  • Ensuring client makes timely decisions on ordering windows, kitchen and bathrooms is important and can stop your project coming to a halt. Lead in times can be anywhere from 6 to 8 weeks.
  • Ensure you get reference’s from your contractor
  • The number of specialty sub-contractors, the more sub-contractors you contractor has can affect how long the project will take.

In this home, the client wants to achieve a Passive House Standard using unique concrete construction.  ICF Insulated Concrete Forms are formwork for concrete that stays in place as permanent building insulation for energy-efficient, cast-in-place, reinforced concrete walls, floors, and roofs. The forms lock together somewhat like Lego bricks and serve to create a form for the structural walls or floors of a building.  This gives the passive house a very high performance in insulation.

The project is now well under construction.

Construction of Bespoke home

Construction of Bespoke home

If you like the idea of our bespoke designs and fancy something a little different, please get in touch.

Ceardean Architects

sarah@ceardean.com

https://www.ceardean.com/services/

01 5324183.

Kildare, Barberstown, Extension - Exterior
,

Ceardean Architects Merge 3 Consecutive Builds In Kildare

Modern Country Living In Barberstown, Kildare

An excellent example where three separate building projects on the one dwelling finally came together in July 2018. A new flat roof extension to the rear left side of the home harmonized perfectly with previous modern extension to the right. The original building was pitched roof throughout.

This dwelling is located near Barberstown Castle in Co. Kildare and was completed in almost record time by AK Builders. Further photos will be presented soon but for now, enjoy these few Client provided shots.

Kildare, Barberstown, Extension 2

Kildare, Barberstown, Extension Two

Simon Community

Dublin Simon Community & Ceardean Architects

Dublin Simon Community

Dublin Simon Community provides services to over 5,100 people and families each year across Dublin, Kildare, Meath and Wicklow who are homeless or at risk of homelessness. Please click on the links below to view more.

Ceardean Architects are delighted to be supporting The Open Door campaign with The Simon Communities.

We have committed a number of slots which are available to book on the Simon Open Door website.

Simon Open Door 2018 Poster

Only a limited number of slots are available to get in touch quickly!

Ceardean

Kildare Extension
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The Home Design Guide – Get You Thinking!

THINK LIGHT. THINK SPACE. THINK HOME.

Ceardean Architects are delighted to offer a short and simple Home Design Guide and it’s for free of course. We don’t even ask for your email.

This guide will quickly get you thinking about what you might want to do and hopefully give you some ideas too.

CLICK HERE!!

Aldo, Shoot over to our Youtube page for loads of videos of past projects for more ideas.

YOUTUBE!!

Simon Community

Simon Open House 2018

Dublin Simon Community

Ceardean Architects

Dublin Simon Community provides services to over 5,100 people and families each year across Dublin, Kildare, Meath and Wicklow who are homeless or at risk of homelessness. Please click on the links below to view more.

Ceardean Architects are delighted to be supporting The Open Door campaign with The Simon Communities.

We have committed a number of slots which are available to book on the Simon Open Door website.

Simon Open Door 2018 Poster

Only a limited number of slots are available to get in touch quickly!

Ceardean

Health

GREAT GREEN GRANT News

Positive Green Action

Read some excellent news from the Minister for Communications, Climate Action and Environment Denis Naughten issued this week.

This news has most likely come because, as a nation, we are a little behind in our carbon emmisions reduction commitments. Either way, offering
grants to households, and businesses, to create and use their own power, is green music to our green ears.

 

Read the full Irish Times article here.

https://www.irishtimes.com/business/energy-and-resources/more-power-to-you-household-solar-energy-grants-on-way-1.3379178

Peace,
Ceardean Architects

Sligo-Cottage

‘One Man’s Quest’ – Our Very Own Derek

Flashback here to a great 2015 article about our chief Architect Derek’s
zero energy cottage in Sligo.

IF RUNNING AWAY and escaping all the madness sounds like something you’d be into -read on.

This holiday cottage originally built in 1820. It was renovated by Derek Trenaman of Ceardean Architects and is a lesson in getting off the grid altogether.

http://www.thejournal.ie/off-the-grid-cottage-2205349-Jul2015/