What do TGD 2011 Part L mean for me?

lostinashford

Hi all,

I have no knowledge of construction but will hopefully be building soon and I want to be on top of what standards I should expect if my house is to conform to current regs regarding insulation etc.. I have an architect but want to have the facts at hand!

I have read the TGD document but most of it is double-Dutch (no offence to any Dutch viewers) to me.

Some simple questions:

Part of the house will be a dormer, what sort of roof/ceiling insulation thickness is required?
Part will be single story wil a flat roof, again what insulation is required?
Will be building with blocks, what wall insulation is needed?
In dormer, should there be insulation in the floor, and if so what thickness?
Should there be insulation on the foundation slab, again what's required?

That's it for starters, thanks for any guidance

I know there's loads of other details needed but at this stage I'm simply trying to get my head around basic figures

DOCARCH

Hi lostinashford

Have you got planning permission yet or have you a design?

A good starting point would be to get a good BER assessor, preferably one with a construction qualification, and start out by getting a provisional BER done. This will help you greatly in guidance in terms of what you need to be looking at to compy with Part L 2011.

It's not all about insulation! In addition to insulation, thing like airtightness, ventilation, orientation, glazing size, renewable energy, size and vaolume of the house, etc, etc, all have to be considered together.

You can no longer just do the elemental method of compliance, i.e. assume that if you get the u-value of your wall, floor, ceilings, etc., to match stated u-values in the Regs, that ergo, your house will automatically comply with Part L - it all has to be considered/assessed together.

If you have started the design process, the provisional BER is invaluable to help you assess all these things in relation to compliance and the design process itself.

BryanF

IMO your question on building regs, is extremely important but maybe the detail of insulation thickness is easier offered by others familiar with your design. The regs in principle require a 60% improvement on the 2005 'boom regs' as required by the eu to save (in principle) co2 and reduce the construction sectors emissions.The ideal client IMHO will want a comfortable home, low energy inuse and low embodied energy materials in construction.. Get the design/ layout, orientation, location etc right first. If you think your there already then maybe you should consider a passive house planning assessment along with the required BER. As docarch says, we have thankfully gotten away from elemental insulation thicknesses but IMO we still have long way to go on achieving the spirit of the 60% co2 reductions the DOE gawked out when issuing the 2011 TGDL regs

lostinashford

What happened to my reply to Docarch!!!

Will do it again in the morning

lostinashford

A provisional BER assessment sounds like a good idea to me Docarch.

Doing solar, rainwater harvesting, good glazing orientation ( as well as enlarging two existing windows to increase solar gain to those rooms)

Question is still what sort of thickness should my insulation be? I understand it's a complete package but can you give me some idea please?

Poor Uncle Tom

lostinashford wrote: »

I know there's loads of other details needed but at this stage I'm simply trying to get my head around basic figures

DOCARCH wrote: »

Hi lostinashford

Have you got planning permission yet or have you a design?

A good starting point would be to get a good BER assessor, preferably one with a construction qualification, and start out by getting a provisional BER done. This will help you greatly in guidance in terms of what you need to be looking at to compy with Part L 2011.

It's not all about insulation! In addition to insulation, thing like airtightness, ventilation, orientation, glazing size, renewable energy, size and vaolume of the house, etc, etc, all have to be considered together.

You can no longer just do the elemental method of compliance, i.e. assume that if you get the u-value of your wall, floor, ceilings, etc., to match stated u-values in the Regs, that ergo, your house will automatically comply with Part L - it all has to be considered/assessed together.

If you have started the design process, the provisional BER is invaluable to help you assess all these things in relation to compliance and the design process itself.

BryanF wrote: »

IMO your question on building regs, is extremely important but maybe the detail of insulation thickness is easier offered by others familiar with your design. The regs in principle require a 60% improvement on the 2005 'boom regs' as required by the eu to save (in principle) co2 and reduce the construction sectors emissions.

lostinashford wrote: »

I understand it's a complete package but can you give me some idea please?

Rather than run the risk of going around in circles here and taking into consideration that you do realise the other elements that need to be taken account of and using the information posted above, if we take the 2005 average insulation for floors, walls and ceilings as being 100mm dense board, 80mm PIR, and 200mm quilt respectively.

Then the current upgraded equivalents are say, 150mm dense board, 130-150mm dense board, 300mm quilt. (This resembles what I ended up specifying on a few jobs lately).

Before I get eaten alive, yes there are a hell of a lot more to be taken account of and each job is taken individually, but the question needed some sort of a tangible answer.

lostinashford wrote: »

What happened to my reply to Docarch!!!

It didn't show up anywhere on the thread, so my guess is that it never completed sending from your side.

DOCARCH

Poor Uncle Tom wrote: »

Before I get eaten alive......

I know the feeling.....!

As a basic initial spec I'd look at something similar (to start with) - 150mm high density floor insulation, 150mm high density cavity wall insulation (if looking at cavity wall construction) plus look at u-values/consider some sort of insulating block in addition, and maybe 400mm quilt/fibreglass attic/roof insulation.

In addition to the above, look at thermal performance/u-values for windows and external doors - go for the best you can afford - look at minimising windows to north facing walls and maximising windows to south facing walls (within reason - also have to consider solar gain/overheating).

Then look at means for making the house airtight - airtight tapes, membranes, etc. - again go for the best you can afford.

Then look at heating systems, solar, ventilation systems, etc.

Don't shoot me! Just trying to help the guy with as simple an answer as possible. Have you a design and/or planning yet lostinashford? All the above should really be considered at the design stage (prior to planning).

sinnerboy

Look to Table 2 here for an overview of how to comply with Part L

lostinashford

Now have planning permission, very happy with design, only 3 small north facing windows (for light purposes), plenty of glazing particularly on South and East aspect.

The reason for the question is mainly because in a preliminary costing by my architect (which I requested for mortgage purposes) he quotes for 60mm Kingspan insulation for the roof! Given what I was reading this seemed low to me (with no knowledge in this area) so want to get some idea of what I should be doing in terms of insulation.

During the design stage I did mention insulation and architect assured me that complying with regulation would give us a very well insulated and efficient home, not looking for passive house but as efficient as possible allowing for budget.

Slightly worried about his spec for the roof insulation

DOCARCH

lostinashford wrote: »

Slightly worried.......

+ 1....:)

What other specs can you tell us?

When did you get planning permission? If it was after 30th November 2011, Part L 2011 applies. If prior to this then Part L 2008 applies (but house must be built by end of November 2013).

lostinashford

Got permission Dec 2011.

In fairness he was reluctant to do an estimate and it is rough (not a lot of detail).

The only depth mentioned is the 60mm between the roof timbers of flat roof and dormer roof (Kingspan TP10 if that means anything significant?)

Only says cavity insulation Kingspan Kooltherm K8 at €20 per sqm

Ground floor insulation Kingspan TF70 at €30 per sqm

Don't want to discredit my architect in anyway (he's been great) but am worried about this obvious error!

Not a lot to go on I know, but thanks for your help, has given me some ideas for my next meeting with him - bank willing!!!!!!

sinnerboy

Get a BER assessor now. One who was designing buildings long before the BER system was born. Ask him/her to run the design through DEAP and present you with options. Do this before you do anything else.

Expect to pay €3/400.00 for the assessment , with a detailed report on your various spec options for roofs/floors/walls/glazing/ventilation/heating/renewables/air tightness. Ask for the xml file so afterwards you can alter things to see "what if" yourself for possible spec alterations.

Your architect may still be good even if weak in this specific area.

lostinashford

sinnerboy wrote: »

Get a BER assessor now. One who was designing buildings long before the BER system was born. Ask him/her to run the design through DEAP and present you with options. Do this before you do anything else.

Expect to pay €3/400.00 for the assessment , with a detailed report on your various spec options for roofs/floors/walls/glazing/ventilation/heating/renewables/air tightness. Ask for the xml file so afterwards you can alter things to see "what if" yourself for possible spec alterations.

Your architect may still be good even if weak in this specific area.

Thanks Sinnerboy, sounds like the way to go.

lostinashford

At the risk of sounding really stupid, can I get a BER assessment done with just the planning drawings or do I need to get my architect to do a first draft of construction drawing?

Thanks for putting up with my ignorance

DOCARCH

You do not necessarily need your construction drawings - the planning drawings can be used - but you would need to have a good idea of your proposed specifications/u-values for insulation (floor, walls, roof, dormers, etc.), windows and external doors, what type of ventilation you intend to have, heating system, whether or not you intend to use solar, etc., etc. You also need to have a good idea on how potential thermal bridging and how air tightness will be dealt with.

Sounds daunting but don't be frightened by all of this, the provisional BER, or more correctly the use of DEAP, will help as a design tool. If their are defficiencies in the specifications, DEAP will help show how the performance of the house can be improved with small changes to insulation, heating controls, etc.

Most important thing is to get a good BER assessor (not the E99 guy!) who will help and advise you and your architect in the design process and get the specifications right.

Just to say that this process should really have been undertaken at the design stage rather than after planning as the more complex or more intricate the shape/design of the house, the harder it is to comply with Part L.

I still see lots of planning drawings for new houses with standard 300mm wide external walls shown! The 300mm wide external wall is probably a thing of the past at this stage.

The knock on of this is that if you already have planning and then you start looking at construction methods after planning, to comply with Part L, you may find your external walls get a lot thicker so this will effect either the footprint of the house and/or make your internal room sizes smaller - this is why now, at the design stage (prior to planning), it is really crucial to tie down your proposed construction specification and have your provisional BER done so at least you know, if you get planning, you can build as per the planning drawings submitted/granted.

lostinashford

DOCARCH wrote: »

You do not necessarily need your construction drawings - the planning drawings can be used - but you would need to have a good idea of your proposed specifications/u-values for insulation (floor, walls, roof, dormers, etc.), windows and external doors, what type of ventilation you intend to have, heating system, whether or not you intend to use solar, etc., etc. You also need to have a good idea on how potential thermal bridging and how air tightness will be dealt with.

Sounds daunting but don't be frightened by all of this, the provisional BER, or more correctly the use of DEAP, will help as a design tool. If their are defficiencies in the specifications, DEAP will help show how the performance of the house can be improved with small changes to insulation, heating controls, etc.

Most important thing is to get a good BER assessor (not the E99 guy!) who will help and advise you and your architect in the design process and get the specifications right.

Just to say that this process should really have been undertaken at the design stage rather than after planning as the more complex or more intricate the shape/design of the house, the harder it is to comply with Part L.

I still see lots of planning drawings for new houses with standard 300mm wide external walls shown! The 300mm wide external wall is probably a thing of the past at this stage.

The knock on of this is that if you already have planning and then you start looking at construction methods after planning, to comply with Part L, you may find your external walls get a lot thicker so this will effect either the footprint of the house and/or make your internal room sizes smaller - this is why now, at the design stage (prior to planning), it is really crucial to tie down your proposed construction specification and have your provisional BER done so at least you know, if you get planning, you can build as per the planning drawings submitted/granted.

As I've said I've have planning so sounds like rooms getting smaller!

Any recommendations of suitable BER assessors welcome - Please PM ANY RECOMMENDATIONS TO COMPLY WITH FORUM RULES

DOCARCH

lostinashford wrote: »

As I've said I've have planning so sounds like rooms getting smaller!

Not necessiarily. That was just more a general observation. All will depend on what construction method you decide to go with and whather you want to just comply with regs or go better!

sinnerboy

lostinashford wrote: »

At the risk of sounding really stupid, can I get a BER assessment done with just the planning drawings or do I need to get my architect to do a first draft of construction drawing?

Thanks for putting up with my ignorance

Don't start construction drawings untill the BER Assesor has completed his part.

He can measure areas off the planning drawings and determine the optimum "mix" of U values / (roofs/floors/walls/glazing)ventilation/heating/renewables/air tightness .

THEN the construction info can follow in an intelligent and informed manner.

lostinashford

sinnerboy wrote: »

Don't start construction drawings untill the BER Assesor has completed his part.

He can measure areas off the planning drawings and determine the optimum "mix" of U values / (roofs/floors/walls/glazing)ventilation/heating/renewables/air tightness .

THEN the construction info can follow in an intelligent and informed manner.

That's great Sinnerboy, tks for all the help, same to everyone else to took the trouble.

Off to find a BER assessor now!

beyondpassive

lostinashford wrote: »

That's great Sinnerboy, tks for all the help, same to everyone else to took the trouble.

Off to find a BER assessor now!

Not to confuse the matter but its also well worth considering putting your scheme through the Passivhaus software as well as DEAP(BER) as it can be a big help in determining the window specification for your particular site and the right heat recovery and airtighness strategy.