A Brief Guide to Building regulations Part L in relation to Dwellngs
Part L of the Building Regulations deals with the Conservation of Fuel and Power. There are 4 approved documents
Part L1A is for new Dwellings ( flats and Houses)
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Part L1B applies to work on existing dwellings or buildings converted to dwellings
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We are specialists in assessment of new and existing dwellings for L1A and L1B. We do not at present assess commercial buildings (L2A and L2B) - If you require a commercial EPC in Kent we are able to recommend someone.
For totally free advice or a quote Telephone Martin Gill on 01634 566215 or 07990556701
Only Use qualified assessors who area members of an approved scheme
It is a legal requirement that new dwellings require an Energy Performance Certificate on completion. For dwellings, this can only be issued by an Assessor who is an OCDEA (On Construction Domestic Energy Assessor) and who is a member of an approved scheme. Building contol should check that you have an EPC before signing off your dwelling. The same applies to dwellings that are created under L1B due to material change of use i.e conversion to flats or houses. Using an appoved assessor ensures that your L1A or B submission is acceptable to building control.
Martin Gill DEA, OCDEA is a member of the NHER scheme member NHER001756 and is a BINDT registered air pressure tester.
If you are designing or building a new dwelling
Before you start building we check that your designs conform to building regulations Part L1a. You send us plans and details : We perform the appropriate calculations and prepare the a report for building control. If we need information that is missing from the plans then we will contact you. We calculate the heating requirement from the details about the space heating and the water heating that you provide us with. We calculate heat losses - from openings and ventilation and through the insulation in the floors, walls roofs .We then perform various calculations to check the compliance with building regulations and which forecast the heating requrement as a SAP rating. We can also issue you with a PEA ( Predicted energy Assessment ) if this is required for marketing off plan.
It is important to do this before you start building - otherwise you risk failure. Some people think that it is sufficient to use certain U values or constructions - but this is not valid , The main criteria for limiting heat losses is that the DER is less than the TER (See below) and this can only be determined using a full SAP calculation. There are other criteria that you must meet (see below) .The new requlations are being amended so that in future you will be required to submit a SAP calculation before you start building
SAP calculations for new dwellings are normally a a two stage process:
At design stage ( before building commences ) : Calculations are used to check that the dwelling meets the mimimum building regulation standards. A target air permeability value is set for the unplanned leakage of air from the structure. We provide all the reports and checklists required by building control.
This includes DER, TER, and predicted SAP ratings. If your designs require modification in order to pass, then we will advise you and discuss any changes required. We often find that some adjustments are required to achieve a pass - we are experienced in finding the best solution for you.
The house is built to the planned specifications:
Single dwellings in most cases will require an Air Pressure Test. We can arange this for you.
Developments of more than one dwelling - a sample of dwellings will probably require Air Pressure Testing - We can advise you on this and arrange a test schedule.
On completion The design calculations are updated with the any changes to the specifications during construction along with the actual air pressure test result. A second report and checklist are generated for building control - and an Energy Performance certificate (EPC) is generated. If the address is new then the address has to be registered on the landmark register of addresses, the official address database cross referenced to EPC's. EPC's are also stored on the landmark datatabase and can be accessed on line for legitimate use if you have the correct report reference code from the EPC. Thus a new hard copy can be generated if the original is defaced or lost.
The completed checklist is used to demonstrate to building control that the building is compliant to part L. Some parts of the checklist sometimes require additional certification or signoff from the builder or installers.
Summary of Criteria in the Checklist
Criterion 1 : predicted carbon dioxide emissions form the proposed dwelling should not exceed the target
Criterion 2 : the perfromance of the building fabric and the heating, hot water and fixed lighting systems syould be no worse than the design limits.
We check the u values of various elements to to make sure that they are not over the limits set out in L1A Table 2
We check the efficiency and configuration of the heating, heating controls and hot water storage against the set standards.
There are certain regulations concerning low energy and external lighting which need to be met.
Criterion 3 : the dwelling has appropriate passive control measures to limit solar gains.
Criterion 4 : The performance of the dwelling as built is consistant with the DER
We provide a list of key features is produced as a standard output from SAP to facilitate sample checking by Building control
Builder states if accredited or non-accredited construction details been used.
Builder states if there is satisfactory documentation of site inspection checks*
We provde the Design air permeability
builder provides evidence that the air permeability has been achieved (Air pressure test results/certificate)*
Builder provides evidence of comissioning of heating and hot water systems (certificate)*
Criteria 5 ; The necessary provisons for energy-efficient operation of the dwelling are put in place
Items marked * require signing off by the builder or other qualified persons.
Existing Dwellings L1B
This typically applies if
you are renovating a dwelling
you are extending or making certain Alterations to a dwelling.
you are converting a building into a dwelling (material change of use)
If you are altering the number of dwellings in a building (house conversion into flats) - material change of use.
You require an extension or unseparated conservatory where there is lots of glazing
(this is not a full list - refer to L1b for a full list of requirements)
In the above cases building control will often ask for a SAP assessment and check that the building is compliant to Part L1B
This is not as clear cut as L1A for new dwellings as the code caters for many circumstances. We are experts in L1B.
There are various schenarios and various methods of compliance - different methods are appropriate according to individual circumstances.
there are also various defences against having to attain standards :
the insulation should be cost effective
measures might compomise the design ( make floor areas too small or floors uneven)
preservation of listed buildings.;
We find that many Building Control offices are not fully conversant with L1B and often request additional and unnecessary measures. Because we are experts in L1B : we can save you time and money and effort. We prepare a fully documented report to present to building control -demonstating compliance with the approprate sections. For overglazed exensions we can often offest heat losses from the glazing by additional savings that can be achieved elsewhere in the house. Sometimes we may require a site visit - if we require additional information so we can present your case fully.
Material change of use calculations will also require Energy performance certificates same as new dwellings. These can ouly be ussued by qualified persons.We are fully qualified under the regulations.
Code for Sustainable Homes levels 2 3 or higher requires a more energy efficient constuction and possibly the use of Renewables such as Photovoltaics