SAPS4u

28/01/2021

A house extension needs a SAP calculation if the glazing is more than 25% of the floor area. This also takes into account any windows and doors that were removed in order to create the extension. If it's more than 25%, you need to do something to compensate for the increased CO2. Our friendly and experienced SAP assessors, Clive and Malcolm, will give you the advice that you need to achieve CO2 compliance with your house extension.

www.saps4u.com

Our team of Accredited SAP assessors provide Fast and Affordable SAP Calculations for New Build and Extensions/Alterations. Call today for your free quote.

28/01/2021

A house extension needs a SAP calculation if the glazing is more than 25% of the floor area. This also takes into account any windows and doors that were removed in order to create the extension. If it's more than 25%, you need to do something to compensate for the increased CO2. Our friendly and experienced SAP assessors, Clive and Malcolm, will give you the advice that you need to achieve CO2 compliance with your house extension.

28/01/2021

Some of my customers are puzzled as to why a house extension sometimes needs a SAP calculation and sometimes doesn't. A house extension can have glazing of up to 25% of its floor area without needing a SAP calculation. This also takes into account the amount of glazing that was removed in order to create the extension, for example, if the kitchen window and door had to be taken out. If it's more than 25%, you need to do something to compensate for the increased CO2. Our friendly and experienced SAP assessors, Clive and Malcolm, will give you the advice that you need to achieve CO2 compliance with your house extension.

www.saps4u.com

Our team of Accredited SAP assessors provide Fast and Affordable SAP Calculations for New Build and Extensions/Alterations. Call today for your free quote.

25/01/2021

The London Plan is derived from the Code for Sustainable Homes. The Code for Sustainable Homes no longer exists and the government scrapped the idea a few years ago. Nevertheless, the Code for Sustainable Homes lives on as many local authorities adopted standards that were derived from the Code for Sustainable Homes.
The government has told most local authorities across the UK that they can not ask for requirements better than Code Level 4, which is a CO2 target of 25% below an ordinary SAP calculation. In London, because of the very high levels of pollution, higher standards than Code Level 4 may be required. The London Plan originally planned to make all homes carbon neutral (Code Level 6) by 2016. This proved too diffiicult.

Why is carbon neutral so difficult? Most buildings that were considered carbon neutral in the past were only considered carbon neutral because they burned wood. Wood is not a clean fuel. It has to be machined. It has to be transported. It also produces particulates - tiny freely floating particles that get into people's lungs. The true definition of carbon neutral is where a building is running on a heat pump and providing enough electricity from its solar panels to replace the amount of electricity it takes from the grid. Over a whole year your fuel bill will be zero. With present day technology, this is difficult to achieve for a building of more than 3 storeys and also requires the designer to adopt a passive house approach from the very start. As soon as you start designing the building, you need to think, how am I going to make this carbon neutral? Which side of the building faces the sun? What thermal bridging system will I use? What insulation, windows and heating system will I use?

Standards have been adopted in London that are as high as are considered technically achievable. Exact targets vary considerably from one local authority to another. An experienced SAP assessor would obtain the specific regulations of the London borough that you are in. This will give you a starting point. It is a good idea to do the SAP calculations first and submit these to Building Control to check before making any final decisions about your project or buying any materials.

Some London boroughs require CO2 emissions 35% below an ordinary SAP calculation. Some also require a 20% further reduction in CO2 emissions due to renewables such as solar PV panels. An Energy Statement is required which shows the building at 4 different stages of development and how the CO2 emissions have been reduced at each stage:
(A) Baseline. This is the building as it would normally be designed to pass a SAP test.
(B) Be Lean. This is the house improved beyond the normal specification needed to pass the SAP test, by improving the building fabric (FEE) and the efficiency of fans, lights and the heating system to achieve a CO2 reduction 35% below the SAP target level.
(C) Be Clean. There is the option to power the building from a community heating network if it is in a part of London where such a system is available. Community heating networks are available in the Olympic Park and Stratford City area and near Kings Cross.
(D) Be Green. Low carbon technologies (such as air source heat pumps) or renewable technologies (such as solar PV panels) are used to ensure that the building achieves a CO2 target 20% below the CO2 level achieved in (B) Be Lean.

23/10/2020

Why does the government want to phase out gas cookers and boilers? Gas produces nitrous oxide and carbon monoxide when it burns. A modern gas boiler is extremely well ventilated and has a balanced flue, drawing air from outside the building into the boiler and expelling the air from the boiler outside of the building, through 2 different holes in the wall. With a gas cooker this is too difficult but you still probably have some ventilation. A passive vent, or maybe two, would have been fitted in the room to help restore breathable air. When you're boiling a pan on a gas stove, the gas flame is right in front of your face. This is probably all right, as you are only burning a small amount of gas. It is rare to get carbon monoxide poisoning if the cooker is installed correctly.

Why is gas controversial? Carbon monoxide poisoning is the worst case scenario. The person would be taken away in an ambulance. But now we're starting to worry more about how low levels of gases like nitrous oxide and carbon monoxide effect our health. What effect do these fumes have on asthma? Are they carcinogenic? Gas has the obvious advantage of being a directly burning fuel. An electric cooker or boiler has to be attached to a power station and a traditional coal fired power station is only 35% efficient. A modern gas boiler might be 89% efficient. But gas produces more of these particulates - more of these noxious fumes that can often aggravate childhood asthma considerably or possibly cause cancer. It produces them either inside, in the case of the cooker, or immediately outside the home, in the case of a modern boiler flue. At least a gas fired power station can be several miles from the city. The government have also been replacing a lot of the old coal fired power stations with nuclear power stations and a significant proportion of electricity is generated from renewables. The new heat pumps are also a lot more efficient than a traditional immersion heater or electric boiler. This makes electricity more environmentally friendly. This is why the government want large housing developments, in the future, to be off the gas grid and electrically heated.

23/10/2020

Some of my customers are puzzled as to why a house extension sometimes needs a SAP calculation and sometimes doesn't. This is to do with the amount of glazing. A house extension can have glazing of up to 25% of its floor area without needing a SAP calculation. This also takes into account the amount of glazing that was removed in order to create the extension, for example, if the kitchen window and door had to be taken out, the area of the kitchen window and the door can be added to this figure. You are still allowed to have an extension with more than this amount of glazing. The purpose of the SAP calculation is to show what you have done to the house to compensate for the large area of glazing you have put into the extension. The CO2 for the house and the extension together has to reach the required target.

10/09/2020

I recently had a client with a large house that was being built on a small budget. I suggested full fill cavity PIR insulation for the walls, as this has become more common in recent years as it has become more difficult to insulate a home to the standard required by the SAP test. It used to be either 50 mm of PIR insulation in a 100 mm cavity or 100 mm of mineral wool in a wall with a 100 mm cavity. The new full fill PIR products give 100 mm of good quality insulation in a cavity wall which is twice as effective and half the U value of the same amount of mineral wool. SAP assessors love this new insulation and some of their customers hate it because it's very expensive. To have full fill PIR insulation you have to create space for the condensation and give the water somewhere to collect in the wall. This means that products like Xtratherm have dimples on the back and products like Celotex have wide spaces with narrow insulation. Adding these features to insulation which, for many decades, has just been a plain board of foam, increases the cost. When my customer complained that this was too expensive, I suggested external wall insulation (EWI) with mineral wool, thinking that it would be very cheap. Mineral wool loft insulation is very cheap but mineral wool EWI is extremely expensive. This is because when mineral wool goes on the outside of a building it has to be made waterproof. A number of companies make Rainscreen products - mineral wool boards designed to go on the outside of a building. These are very expensive because mineral wool is naturally very water absorbent and making it sufficiently waterproof to go on the outside of a building is very difficult. My client eventually decided to use external PIR insulation which was a fraction of the cost. PIR is a lot more water resistant than mineral wool and it is easier to produce PIR products which are sufficiently waterproof to be used on the outside of a building.

19/09/2018

When you replace one of your windows with double glazing, why doesn't the house fall down? This is because there is a lintel above the window that holds up

26/04/2018

You should have a SAP calculation while you are still at the planning stage before you start building - I would advise even before you buy any materials. It is very likely that your building, as you've designed it, isn't compliant and that the SAP Assessor will need to give you a great deal of advice about how to put it right. Making changes to a building when it is completed can be expensive. It involves increased labour costs and may include an extra layer of insulation on the inside walls or additional solar PV panels. These may have been avoided with careful design at an early stage.

19/04/2018

A lintel is placed on top of a window to hold the wall above it together. It is usually made from metal. Insulated lintels improve the SAP rating of a new build house considerably. They have a rigid polymer (very strong plastic) and a block of polystyrene in the middle which forms a thermal break and stops the heat going out of the house through the lintel. But you can't use standard insulated lintels with timber frame walls. SAPS4U can advise you on how to fit windows in a timber frame wall in a way that produces the same effect as a standard insulated lintel.