|Posted by wilkinsoncc on July 30, 2018 at 8:30 AM||comments (0)|
Geoff Wilkinson looks at problems arising from failure to identify where drains run
One of the most frequent problems we see with small projects arises from the failure to check whether or not there are drains running beneath the footprint of a proposed building or extension.
Building Regulation H4 requires that when building within 3m of a public sewer, or within 1m of a public lateral drain, you’ll need water authority approval before work begins. Even if the drain is not a public sewer or shared drain, failure to identify the location of the drain can still cause major issues if there is a conflict between the line of the drain and the line of the structure above.
Failure to identify the depth of the drain can also cause problems. A shallow drain might be too shallow to enable drainage from the new project to function correctly, or it might clash with the floor slab. Equally, a deep drain might require significantly deeper foundations than were originally assumed or priced for.
The RIBA Plan of Work for small projects places the production of drainage plans in Stage 4, but this is too late if the drains are found to clash with the building – which can require a full reapplication to be made for planning permission.
Instead I would recommend that a search for the location of drainage should be conducted at Stage 2, when the feasibility of the project is considered, and prior to obtaining a planning consent that may simply not be buildable.
Access points on a sewer may need to be relocated as part of the works and included in the design
It should be remembered that the Building Regulations state that in some soils, such as sands or silt, buildings must not be constructed over or within 3m of a drain unless special measures are in place.
Additional restrictions apply if the drain is a rising main, constructed of brick (a traditional Victorian culvert, for example), or if it is damaged or in poor condition.
Buildings and extensions should not be constructed over a manhole or inspection point on a sewer. Access points on a sewer may need to be relocated as part of the works and included in the design. The extension must also maintain a 3m zone to enable the sewer to be reconstructed in the future if the water authority deem it necessary, and that zone should also be accessible to a mechanical excavator, depending on the depth of the drain.
Building Regulations also restrict the length of drain or sewer that can be built over to a maximum length of 6m.
Lastly, if the drain is greater than 225mm in diameter or greater than 3m in depth, then again special consent will be required, which could affect the viability of the project.
In most cases applying for permission is simple and can be done using a self-certification questionnaire online, although some water authorities are much more helpful than others and a simple national system would help remove regional variations. If you aren’t able to self-certify, you can instead apply for an approved build-over agreement, which should be supplied to the Building Control body prior to the works commencing.
If a build-over agreement is required, then a number of important restrictions are likely to apply. These vary by water authority, but typically include:
So: don’t leave it too late in the project to check where the drains run; ideally, pick it up during the initial site survey.
This article originally appeared in the May issue of AJ Specification
Illustration (C) Thames Water Utilities Ltd https://developers.thameswater.co.uk/Domestic-and-small-commercial/Building-near-pipes/Building-over-or-near-a-sewer
|Posted by wilkinsoncc on June 15, 2018 at 11:15 AM||comments (0)|
The Regs: How to get a highly glazed extension to comply with Building Regulations
If you have ever wondered how an architect got that glass box extension past building control, then Geoff Wilkinson has the answer
There has been a huge trend in demand for extensions that join internal living spaces to the garden by way of large areas of glazing and ever larger opening bi-fold doors. However this sleek and transparent look desired by homeowners can be at odds with Building Regulations Part L, which sets targets for the building envelope’s energy efficiency.
Part L limits the total area of openings or glazed elements, such as windows, roof windows and doors, to a maximum of 25 per cent of the extension’s floor area. A small extension with a set of patio doors and a lantern light can easily use up this 25 per cent allowance.
An extension that exceeds the allowance is generally referred to as an ‘over-glazed extension’, but they can also be known as sun rooms, orangeries or even glass-box extensions.
Architects will find that, where the 25 per cent rule is exceeded, building control will either reject the plans or request further justification for the over-glazing. So how do you get an over-glazed extension to comply?
Well, although the extension is not compliant on an individual element basis, it could still pass L1B regulations using one of the alternative methods set out in the approved document.
The first thing to do is to deduct the total area of any windows or doors that, as a result of the extension works, no longer exist or are no longer exposed. This is because the heat lost through these elements is no longer being lost. In many cases you will find that this is all you need to do, and a quick schedule of openings versus covered openings may be all that you need.
For example: if an extension has a floor area of 30m² and is covering an existing patio door with an area of 4m² then the extension is allowed to have 6m² (25 per cent rule) plus 4m² (existing openings rule) making an allowable area of 10m². Submit that with your Building Regs application and it’s likely to sail through the checking process.
But if this still isn’t enough then the next option is to demonstrate that the proposed extension is no less compliant than if an extension of the same size and shape was built according to the 25 per cent limit. For example, you could increase the thermal resistance (U-value) of the walls, floor, roof, or glazing elements above the default values in order to increase the area of glass.
From experience I can say that in most cases the heat loss though the glazing will dominate, so start there. Given that the default U-values for walls, floors and roof should all be in the range 0.16-0.28W/m2K, there is not much you can do to significantly improve these. However, the notional glazing has a U-value of 1.6-1.8W/m2K and means that high-performance, gas-filled, low-e-coated glass could see the U-value tumble to 0.9 or better, allowing you more than 40 per cent glazing. Take out some covered-up openings and a 50 per cent glazing ratio is easy to achieve.
But if the extension is very highly glazed (more than 50 per cent), you may need to use the Standard Assessment Procedure (SAP). These calculations should be carried out by an accredited SAP assessor, and demonstrate that the calculated carbon dioxide (CO2) emission rate from the dwelling with its proposed extension would be no greater than the dwelling and a notional fully compliant extension of the same size and shape. This method allows you to keep almost 100 per cent glazing by upgrading existing elements and services within the original part of the house instead – for example, by installing a more efficient heating and hot water system, or increasing the insulation within the existing roof space.
The SAP method allows you to keep almost 100 per cent glazing by upgrading existing elements within the original part of the house
The building control officer may well confuse matters by asking for ‘excess glazing calculations’, ‘SAP calculations’, ‘heat loss calculations’ or ‘thermal calculations’, but in truth all four terms mean the same thing. If you are not qualified to carry out these calculations yourself then I would recommend Googling ‘heat loss calculations for over-glazed extensions’ and you will find a number of consultants that can produce them for you.
In many cases it’s only a couple of hours work for them and a budget of £250 can usually cover it – a small price to pay for that award-winning, highly glazed look on your project.
This Article first appeared in Architects Journal https://www.architectsjournal.co.uk/opinion/the-regs-how-to-get-a-highly-glazed-extension-to-comply-with-building-regulations/10022424.article
|Posted by wilkinsoncc on May 31, 2018 at 7:55 PM||comments (0)|
Congratulations to our longest serving employee Chloe Still on her marriage to Dave Prentice on 24th May 2018.
The Wedding took place in the fantastic venue at the Lost Village of Dode and even featured both a Owl and a Magician.
We wish them both the very best for thier future together
|Posted by wilkinsoncc on May 29, 2018 at 8:40 AM||comments (0)|
The Regs: Don’t get your fingers burnt on a kitchen project
Geoff Wilkinson looks at the potential pitfalls of kitchen, utility and bathroom schemes
Work to a kitchen, utility room or bathroom can seem like the simplest of projects an architect can deal with, but they can be a minefield if you aren’t sure when you need Building Regulation approval.
A very simple refresh with new units and fittings does not generally require approval, however moving sanitary fittings such as the sink or toilet or carrying out electrical works as part of a refit may do so.
Source: Agnese Sanvito
Whitehill Farm, Dunstable, by Hampson Williams Architects
If a bathroom or kitchen is to be provided in a room where there wasn’t one before or you are knocking down a wall (loadbearing or not), Building Regulations approval is likely to be required to ensure the room will have adequate ventilation and drainage, and meet requirements in respect of structural stability and electrical and fire safety. If in doubt always check with a building control body – either the local authority or an approved inspector. Here’s a quick guide to some of the pitfalls to look out for:
Part A Apart from the obvious issues of removing a structural wall, if you are changing the use of a room (eg installing a large bath or jacuzzi in a bedroom) this could increase the load on the floor structure and require strengthening the floor.
Part B Making an open-plan space by removing doors or walls between the kitchen and other rooms, particularly to a staircase, will affect means of escape. Additional precautions in other parts of the property may be needed, such as escape windows, interlinked smoke and heat detection, additional fire resistance or even sprinklers.
Part F When inserting or removing an internal wall, care should be taken not to make ventilation worse. Any new kitchen, a toilet with no openable window; a bath/shower room or utility room should be provided with a mechanical extract fan. The type of room will determine how much ventilation is required. Part F says that where a kitchen previously had only a recirculating fan this can be retained/replaced if it is made no worse. However, I would always recommend fitting an extractor to deal with condensation.
• Kitchen: 30l/s if over the hob and 60l/s if placed elsewhere
• Bath/shower: 15l/s with overrun
• Toilet: 6l/s with overrun
• Utility room: 30l/s
Part H Replacing existing fittings on a like-for-like basis is not controlled. However, if the installation of the fittings will extend or make new connections to a drainage stack or an underground drain, the above-ground wastes and drains are controllable.
Part L If you install or replace a window or external door as part of the works, it will need to comply with Part L Heat Loss in all cases. It may also need to comply with Part A Structure if the opening is made wider; Part K Safety Glazing if the glass is at low level; and possibly Part B Fire Spread if the glass is within 1m of the boundary, for example.
Part J This obviously applies if you install a new boiler, but also if you move the boiler to another location or even if you leave the boiler where it is but extend the flue. Also, if hiding a boiler in a cupboard, take care to ensure there is adequate ventilation and access for servicing.
Part M Another area where you may get caught out is simply moving a ground-floor toilet, since most houses constructed after 1999 will have a ground-floor toilet installed, which has been designed to cater for any visiting wheelchair users. During any refitting, this toilet should not be removed and the accessibility of the toilet should not be made any worse, as it would then be inadequate for future wheelchair users.
Part P Electrical work may be non-notifiable unless a new circuit is provided. For example, installing a new built-in cooker or prefabricated modular lighting is non-notifiable unless a new circuit is required. Even so, be wary of affecting:
• structure (depth of chases in walls, notches in floor and roof joists)
• fire safety (fire resistance of penetrations through floors and walls)
• sound (service penetrations on party walls)
• replacing energy-efficient lighting with inefficient lighting
If a new circuit is being installed or it is within a wet zone (eg adjacent to a bath or shower) then it will require approval or self-certification under Part P.
This article originally appeared in the https://www.architectsjournal.co.uk/opinion/the-regs-dont-get-your-fingers-burnt-on-a-kitchen-project/10031324.article#" target="_blank" rel="nofollow">April issue of AJ Specification
|Posted by wilkinsoncc on May 21, 2018 at 8:55 AM||comments (0)|
The Hackitt report was published last week and like many we were shocked at its conclusions, and importantly its lack of them in relation to cladding.
Given the clear case for action on combustible cladding and the ease with which an amendment could be made by issuing a corrigenda amendment to Approved Document B, we cannot understand why Dame Hackitt did not make this move a top priority.
As it stand there are no changes to the guidance in the Approved Documents and designers and contractors could continue to use Desk Top Studies to justify the use of untested cladding systems. This simply cannot be right.
We note that LABC have produced guidance saying they will continue to accept not only method 3 desktop studies but even method 4 studies subject to certain restrictions. This is all the more concerning as Dame Hackitt has suggested that only LABC should continue to approve High Rise buildings effectively banning Approved Inspectors working on them. This despite both Grenfell Tower and Lakanal House being Local Authority projects.
Over the next few weeks we will be making a series of posts reviewing the Hackitt report and setting out what we believe to be a better and more logical solution to the problems with the current system.
However in the meantime whilst we can continue to deal with High Rise Buildings (and in the longer term on buildings between 18m and 10 storeys) WCCL are today announcing the following policy.
1) We will advise clients to adopt the following strategy set out in BS 9991 2015 as though it supersedes the Approved Document - e.g.
• The external surfaces of walls should meet the provisions in Figure 17.
• In a building with a storey 18 m or more above ground level, any cladding material, insulation product, filler material (not including gaskets, sealants and similar), etc., used in the external wall construction should be of limited combustibility.
• Cavity barriers should be provided in accordance with Clause 19.
• External balconies that are enclosed should be constructed and separated from other enclosed balconies with compartmentation and fire-resisting construction in accordance with Annex D.
2) Where clients wish to use combustible construction despite our advice, then the external walls must meet the performance criteria given in BRE Report BR 135 for cladding systems. We will require full scale test data from BS 8414-1 or BS 8414-2 for the exact system to be used. We will not accept any variation from those test results and or desk top studies in any form to justify the use of combustible materials in systems that have not been tested.
We appreciate that this policy may result in losing projects to other BCB who do not take this approach and that this approach may be challenged by those producing combustible cladding products. However, pending the full outcome of the Grenfell Inquiry and revised updated guidance being issued by MHCLG we do not believe that it is appropriate to do nothing. We therefore call upon all BCB and those involved in construction to adopt the same consistent approach and to provide reassurance to those living and working in high rise buildings that cladding is safe.
|Posted by wilkinsoncc on May 8, 2018 at 5:45 AM||comments (0)|
The much awaited Hackitt Report into the future of Building Control is due to be published soon.
In this blog we look at the changes to the system that we would like to see in the recommendations.
Many of these ideas are hardly new and most have been around since the Future of Building Control Implementation Plan published in 2009 a report that has still not been implemented by either the coalition or the current Government.
|Posted by wilkinsoncc on April 16, 2018 at 6:15 AM||comments (0)|
Just moved home or about to renovate your living and kitchen space? The trend for opening up a property – removing walls to get that amazing feeling of space, as well as making your mark on your home or a new house – continues to grow. However, going open-plan can be a Building Regulations minefield; there are various issues you may come up against, but the key focus is always fire safety. As you weigh up your design options, here are some tips to help you to create a safe and legally compliant open space.
What are the main Building Regulations issues for open-plan spaces?
The main issues associated with open-plan areas are fire safety and safe escape.
For example, is your staircase separated from your open-plan space by a fire door to allow a safe passage out of the building from other parts of the house? Is the kitchen – which is, of course, a fire risk area – closed off by a fire door? What about ventilation? One of the most common questions I’m asked when it comes to open-plan spaces is how to work around the issue of the kitchen fire door, which many people don’t want to install.
You might hear about friends or neighbours who plan to get their Building Regulations Certificate and then remove the fire doors the regulations stipulated they must have, but which they never really wanted. Be aware that this is not only illegal, it’s also unsafe: the regulations are designed to save your life.
So before you get swept away in the excitement of your new, open-plan space, it’s important for your architect to consult with Building Control sooner rather than later to ensure your design is actually achievable. (More on Building Control inspectors shortly.)
If you’re still deciding on your design, take a look at lots of open-plan kitchens for more ideas.
Is there a fire escape route?
One of the major questions your architect and Building Control officer will ask is, ‘Will it be safe to escape in the event of fire?’ It’s an issue nobody should take lightly, and even though dealing with it often makes open-plan spaces more difficult, it’s nevertheless important to stick to these rules.
For example, a staircase providing an escape route from upstairs rooms wouldn’t generally be allowed to go through the kitchen. This is because the kitchen is considered a fire risk, and therefore no escape route should lead through it. Staircases are escape routes as well, and usually all rooms need a 30-minute separation – in other words fire doors – around them on the ground floor. The only way an escape route could lead through a kitchen is if you have a mist system installed, or sprinklers.
In this open-plan space, no doors are needed between the kitchen and reception rooms. Why? Because there’s a ‘secondary escape’. Read on for more about these.
Is there a secondary fire escape?
In order to create an open-plan living/kitchen/dining area like this one (the living area is where the photo has been taken from), you’ll need to have an alternative fire escape, or what Building Regulations terms a ‘secondary escape’, from these areas.
These escapes could be doors into the garden, or even windows, provided they are of a minimum size. If this is the case, you may not need to separate your kitchen from your diner and your living space with doors.
Do you need a sprinkler system?
Sprinklers, already touched upon earlier, are probably something most homeowners want to avoid having to install, especially as they can be expensive.
However, since Building Regulations states there must be a safe passage through open-plan spaces adjacent to stairs, this could be the only solution for this kind of layout, as escape routes are made safer if a fine water mist is ‘sprinkled’ in the event of fire, allowing for more time to escape.
You need to consider sprinklers when:
Is there sufficient kitchen ventilation?
In open-plan kitchens, mechanical ventilation needs to be installed for the kitchen extractor. A recirculating design is not sufficient, because not only do extractors get rid of smells, CO2 and other harmful gases, they also remove water vapour, which is created when you cook. Without correct extraction, mould can grow, just as it would in a bathroom without ventilation.
A side point here, back on the topic of doors: at the rear of this open-plan kitchen, there are double doors closing it off from the hallway, staircase and front door, which in the event of a fire in the kitchen provide a safe exit from the staircase. If you want to install glazed doors in a situation like this – as here – you’ll need to ensure the glass is fire-rated.
Is the glazing safe?
Any glazing below 800mm needs to comply with safety standards and to meet Building Regulations requirements. This would apply, for example, to secondary escape route doors, such as the external glass patio doors pictured here (as well as the internal doors pictured previously).
Fire-rated glass must have confirmation from your supplier that it meets required safety standards, and there should also be a sticker on the glass to prove it. The sticker is key, as without it you have no proof the glass is safe, and you wouldn’t get a Building Control Certificate.
How do I ensure split-level open spaces comply?
If your open-plan space is not all on one level, don’t worry. As long as the steps from one level to another are like your stairs, and therefore not considered a ‘trip hazard’ (as a barely noticeable threshold would be), you will be fine.
With higher than usual spaces, safe fire escape routes are different. The same rules apply, but they can be challenged with the help of a fire consultant’s report. This includes calculations to prove that, for example, the escape route can be longer because there is more void above, which needs longer to fill with smoke (meaning it’s OK if people need more time to escape).
If you have such a space or would like to create one, I’d always suggest using an approved inspector, which means a private company can give you a Building Control Certificate. This type of inspector is, in my experience, more likely to be flexible with interpreting the regulations, while of course keeping your safety in mind as a priority at all times.
Can I have sliding doors?
How often do you close the door to your kitchen in an otherwise open-plan space? Probably rarely or never. Since, however, a fire door is required, and the cost of a fire shutter or sprinklers is much higher, let’s consider pocket sliding doors. This solves both of these issues – you are still safe and legal, and by sliding the door into the wall, the sense of open space remains.
New regulations do allow sliding doors into kitchens in open-plan spaces. (Previously they were not allowed at all.) A few years ago, such doors needed to be self-closing, but the regulations have been adapted. However, if the door is glass, as seen in this room, it must also be fire-safe as described earlier
First publish on Houzz
Michael Schienke 18 December 2015
Houzz UK Contributor. Chartered Architect, director and founder at Vorbild Architecture Limited. The company was established in 2007 and specialises in a "one stop shop" services including land search, budget advice, planning application in the UK and France / Monaco, interior design, tender package, site supervision, contract management and full architectural and interior design services, as well as specialist services like : site and property search, feng shui consultation, client supply sourcing, furniture design and sourcing and landscape design.
|Posted by wilkinsoncc on June 26, 2017 at 1:45 AM||comments (0)|
20 Questions that should be answered quickly in the light of the Grenfell Disaster
(originally posted on twitter on 16th June 2017 by our MD Geoff Wilkinson @geoffwilkinson)
1: Can we see the Architects plans & specifications?
2: Were these approved?
3: Were the fire service consulted?
4: Can we see a copy of the consultation respons?
5: How many site inspections were made?
6: Can we see records of those inspections?
7: Were the approved materials used or was there a "value engineering exercise"?
8: Did the contractor rely only on the minimum statutory inspections or did they employ their own clerk of works to inspect?
10: Was the fire risk assessment updated as a result of the works?
11: Can we see a copy of the fire risk assessment?
12: What recommendations did the fire risk assessor make?
13: Were those recommendations acted upon?
14: Was any further work (e.g. Gas main) carried out after the building control sign off?
15: If so did that work require approval?
16: When was the last fire risk assessment carried out?
17: When were fire doors last checked?
18: When were emergency lights last tested?
19: When were smoke control systems last tested?
20: Can a sample of the cladding be taken off and tested urgently and publicly?
|Posted by wilkinsoncc on June 25, 2017 at 3:55 AM||comments (0)|
Advice on what to do to reassure residents
Here is the current guidance for landlords in light of emerging findings from Grenfell Tower
If you discover that the cladding and insulation are of the same type used in Grenfell or fail the test then there are some emergency measures that you should immediately implement to ensure the safety of residents, pending replacement of the cladding
Notify Fire and Rescue Service.
Inform your local fire and rescue service fire safety/protection department. Failure to do so may put fire-fighters as well as residents at risk. The fire and rescue service will carry out an urgent inspection with the ‘responsible person’ to ensure that they are identifying and introducing appropriate interim measures, as set out below. The fire service will carry out a further inspection once the interim measures have been completed:If the building is protected by an automatic sprinkler system (or equivalent fire suppression system) you might not need to take any further interim measures before replacement of the cladding.
If the building is not protected by a suitable suppression system you must consider the need for interim measures. The measures adopted need to be based on an assessment of the risk by a competent person, but the following must, at least, be considered:
- Residents to be advised to ensure all smoke alarms are present and working in their flat; to report concerns about fire safety measures in the building (eg presence of combustible materials in escape routes) to their landlord and, understand the purpose of any interim measures being taken.
- Closure of car parks in which a vehicle fire could impinge on cladding.
- Provision of a temporary communal fire alarm system, comprising smoke detectors in circulation areas and plant rooms, and fire detectors (possibly heat detectors, rather than smoke detectors) in conjunction with fire alarm sounders in each flat. This will enable the entire block to be evacuated simultaneously in the event of fire. This option is unlikely to be suitable for tall blocks, in which a large number of people would need to use escape routes at the same time. The system may comprise a wireless system, using radio to link devices.
- Provision of a fire watch by appropriately trained patrolling security officers/wardens.
- In the case of the most serious risk, consideration must be given to moving all residents out of the block until satisfactory remedial work has been done.
|Posted by wilkinsoncc on September 5, 2016 at 1:15 PM||comments (0)|
This week sees the 350th Anniversary of the 1666 Great Fire that devastated London and led to the introduction of the first proper system of Building Regulations in the UK
Laws had previously existed to reduce the risk of fire, prohibiting building with wood or roofing with thatch, but these laws had largely been ignored. Despite a number of previous fires timber-frame remained the most common form of construction in and as the population grew, so buildings were extended upwards creating jettied timber houses overhanging narrow streets.
The fire started in Pudding Lane in a baker’s shop owned by Thomas Farriner – who was the king’s baker His maid failed to put out the ovens at the end of the night, and the heat created by the ovens caused sparks to ignite the wooden home of Farriner. Strong winds fanned the flames and without any form of fire break the Great Fire spread rapidly between buildings, resulting in an estimated 80% of the city being destroyed and 70,000 people being made homeless. It was only the Thames that prevented the Fire spreading south and even greater losses.
That disaster led to the London Building Act of 1667, the first to provide for surveyors to enforce its regulations. Charles II decreed after the Fire that the City would be rebuilt in bricks or stone, and that streets should be wide enough to act as a fire break to prevent the spread of fire from one side to another. The number of storeys and width of walls were carefully specified.
Sir Christopher Wren was amongst the group tasked to draw up these regulations which became known as the London Building Act of 1667 and which applied to the walled City of London. Further acts of 1707 and 1709 extended control to Westminster, and by 1774 Building Regulations covered the whole of London. These Act's also included requirements for structural load-bearing walls, foundations, timber in party walls, joist centres, beam bearings, roof coverings and rainwater gutters and down-pipes, and was enforced by newly created District Surveyors - the fore runner of todays Building Inspector. Remnants of this system - the 1939 London Building Act (Amendment) Act and District Surveyors - still exist in London to this day.