Monday 30 January 2017

What can we do to help Oxfordshire’s flooding issue?

Oxford’s Flood Alleviation scheme has provided a glimmer of hope for local business and property owners following severe flooding in 2003, 2007, 2012, 2013 and 2014. Oxfordshire Growth Board have recently announced the scheme has been put on an amber status, now there is a substantial financial gap in funds of £10m. Although the people of Oxford have been reassured the project will continue, allowing the construction of the four-mile flood channel, Rodney Rose, Oxfordshire County Council’s deputy leader, has invited local businesses to contribute financially to the scheme. With some expressing doubt on the willingness of local people to do so. 


The plight of Oxford and its flooding issues, as well as the problems experienced by the rest of the UK, highlights the need to incorporate Sustainable Drainage Systems (SuDS) in any development, and that strategy is at the heart of all we do.

The necessity for Sustainable Drainage Solutions (SuDS)

Oxfordshire has seen its fair share of flooding in recent years, affecting roads, railway lines, schools, businesses and homes, and with substantial urban development and bodies of water in abundance, the issue is unlikely to ease any time soon. The aspects that need to be addressed when designing new developments are the quantity of water (flooding), quality of water (pollution), biodiversity (wildlife and plants) and amenities.

Sustainable Drainage Solutions, (SuDS), should mimic nature, managing rainfall where it falls, but also need to consider the affects they may have downstream on nearing communities; the idea is not to simply transfer the flood risk elsewhere. Creating zero, or minimal, long-term detrimental damage, SUDs are considered the environmentally friendly option.

It’s quite often felt that the look of such SuDS is crucial to its initial appreciation within the community, so not only do the designers need to consider the most effective way to incorporate SuDS, they also need to be aware of its appearance, taking into account the style of the area, ensuring it fits visually.

In order to optimise the benefits of SuDS, the planning and design needs to be incorporated at the start of the development process. Fitting in sustainable drainage mid-way through a project is likely to result in the SuDS being less effective than what it could have been if it was considered holistically, creating problems down the line when the heavy rainfall begins. Additionally, continual efforts to perform a sequence of management practices, control structures and strategies ensures the recurrent benefits of efficient and sustainably drained surface water, all while minimising pollution of any local water bodies.

What do we do to help?

Our designers believe in the importance of a holistic solution for the disposal of surface and foul water, working with the client to develop sustainable drainage techniques from the beginning. To us, sustainable drainage is not an afterthought, and there is no “one size fits all”, therefore each site needs to be assessed individually. 


Implementations from Gemma Design

Here at Gemma Design, we use the very latest hydraulic design software and computer systems, combined with detailed knowledge of current design standards, to deliver integrated solutions for challenging and complex sites.

Where off-site disposal is necessary, we demonstrate a proven track record of securing consent from statutory authorities, through both Section 104 and 106 applications, and land drainage consent, for discharging to watercourses, therefore actively adhering to all local guidelines.

Disposal of foul drainage can be challenging where no existing connections are present, or the infrastructure is at a shallow depth, and in these situations, treatment is needed. Our engineers liaise with the Environment Agency to obtain approval for any on-site treatment, and with sewage undertakers for the installation of pumping stations where necessary.


As flooding becomes an increasing problem, we will continue to carry out any necessary assessments, systems and procedures to continue to develop in the most environmentally sustainable way possible.

Thursday 26 January 2017

Aston Martin Dealership – Bristol

Client: Aston Martin
Architect: NC Architects Ltd

Gemma Design was commissioned to work on this split level dealership over three floors, for Aston Martin; a prestigious car manufacturer. The project called for sophistication within the design, emitting style and luxury, whilst tackling the geographical and logistical challenges of the site.

The proposed plot was on a long slope, so the major consideration for this scheme was the provision of level platforms for both the building and the surrounding parking areas. There was a difference in site levels of 8 meters across the site with three existing roads and one dwelling in the vicinity, so the design had to incorporate various access points and the neighbouring dwelling.

Gemma Design, along with NC Architects Ltd, were able to approach this design collaboratively using a 3D ground model, enabling them to maximise the use of the natural slope and incorporate it into the design, thereby eliminating the need for earth retaining structures. From the front of the building, the dealership appears to be of a single level, approached by a large gradient drive way. The wall to the right frames the glass fronted showroom, whilst hiding the falling slope to the back concealing two additional floors built in to the natural slope of the land.

The new Aston Martin Dealership upon arrival
The building has a number of interesting constraints, most notably an internal clear span of 32m at roof level, with the main showroom, above the workshop hidden from sight, spanning just 20m. The 8m cantilevered roof section to the front of the building adheres to the style and sophistication required for such a luxury brand.

The design was made more challenging by the request to reduce the height of the building by 1m, consequently reducing the available structural zones. The specifications weren’t possible using traditional rolled sections, therefore cellular beams were chosen to meet the client’s revised brief.

Incorporated cellular beams by Gemma Design
Careful consideration had to be given to the potential for the show room to vibrate, in resonance with V8 engines of the cars, when traversing the showroom. Using CellVibe, a software package developed by the SCI, the floor plate was analysed to look at the behaviour of the floor system. Gemma Design calculated the accelerations and response factors of the floor to demonstrate that the building didn’t vibrate and cause discomfort to the occupants every time a new car was rolled in or out.
The vibration of the floor is controlled by the system as a whole, i.e. not just the floor slab, but the primary and secondary beams as well. Therefore, it is essential to view the design holistically, understanding how they can work together rather than individually. Using an appropriate software package, allowed Gemma Design to do so.

Aston Martin Dealership 
To see the new dealership for yourself, the address is Vantage Point, Cribbs Causeway, BS10 7TU or visit their website for more details: http://www.dicklovett.co.uk/aston-martin/


Friday 30 September 2016

Making the most of a small plot

Gemma Design is a structural engineering company that believes in staying ahead of the game; we embrace technology advancements, stay informed of the trends in commercial and home building and tackle the increasing issue of maximising the potential of small building plots. We ensure we know how the industry is changing and the demands that are put upon it.

One of those demands is on land provision to satisfy the desire to build new homes, not for the developers, but for the family. This increased demand on self-build plots makes it a necessity to exercise our ingenuity and innovation for making the most of a small plot of land. With land at an absolute premium right now and with the Government making self-build a dream come true for many, it falls to the expertise of the engineer and architect to make sure a small plot becomes a large family home.

One self-builder from Cornwall, Max Marshall, saw the answer in an Eco-Hubb. Not only is it fully sustainable, it cost a minimal £15,000 and fit in his parents back garden. A diverse option for an office, gym, rented living accommodation or just some extra space that doesn’t cost the earth.

How Gemma Design delivered on small plots

Gemma Designs’ engineers are increasingly working with unusually shaped plots, discovering that embracing height opportunities as well as unique shapes lead to innovative design and engineering solutions.
One such example of problem solving can be seen in Rookery Cottage.



What was a two-storey cottage in Old Headington is now a four-storey semi-detached town house, allowing for additional space for the occupants and providing investment for additional income. Planning issues with height restrictions were overcome by embracing the existing 40 meter fall from front to back of the plot and digging down into the ground. The site was tight, owing to existing trees both within and external to the site, but as you can see from the schematic, design is all important in preservation.


Cumnor Hill Flats

With the flats at Cumnor Hill in Oxford, there was very little structural floor depth to make the irregular wall layout work. All floors compensate for this owing to the exceptional 150mm thickness.
A large retaining wall was used to create the volume of space required here, which was strictly limited, and the ingenuity of the engineers played an integral part of the success of this project with the innovative and clever designs.

In addition to space limitations the local badger population presented a protection issue, which was solved by a new culvert, and sustainable drainage solutions were provided with a permeable paved car park, providing essential parking areas and even more essential flood prevention.



For ingenious and innovative design for your next self-build project, contact Gemma Design's engineer team on 01993 705522.


Wednesday 31 August 2016

How BIM technology benefits clients – Part Two: When modern tech meets history with the Anstey Hall Project

BIM is a zero impact application and therefore beneficial for the entire life of a building, even those with a complex and delicate construction.

Although BIM reduces many complications and promotes advantages in the planning stages of construction, the difficulty remains in the interpretation of the components of features which were originally constructed before modern safety standards or before modern techniques – fireplaces, doors and windows for example.

In this instance, intelligent object recognition steps in, usually with an architect in tow, to measure and interpret the core of these features. BIM then comes in once again to receive this information and incorporate the 2 dimensional data, resulting in a comprehensive 3d map of the building and its constituents.

Digital Barn series by Gemma Design

A recent project by Gemma Design has brought about these very challenges. The Anstey Hall project involves the creation of 12 new bespoke dwellings and the restoration of eight listed timber and brick barns. BIM has been utilised from the first day of engagement, incorporating any 2d drawings already available.




Sensitive restoration in this case, is to be coupled with the addition of internal mezzanine steel frames and new extensions. The client is embracing the use of BIM, to ensure the mezzanine floors are fully independent of the existing structure and to map out the engineering solutions required to achieve this, whilst producing a striking and contemporary finished project.



Early engagement of technology

Applying BIM technology to historic buildings is part of Gemma Designs’ commitment to early engagement with technology. There is at this point in time very little research published on the use of BIM for historic buildings, which makes us feel like pioneers in the industry, although according to those at the ‘coal face’ if you use BIM, you will use it on all of your projects, wherever possible. So not only do we apply technology early on in projects, but we like to embrace the use of innovative technology as it emerges too.

This begs the question, why is there little data published on the use of BIM for historic buildings?

There is no real answer to this question, other than that BIM was initially adopted by industries to aid the modelling and collaboration of trades on new buildings, and since the roll-out of BIM as a tool has been staged in levels, it could be classed as still in it’s infancy.

BIM for all

The purpose of the innovation of BIM technology is to aid collaboration across the architectural, engineering and construction industries. It is a vital tool for accuracy as well. Virtual renovation and reconstruction allows for the structural integrity of the building and for the feasibility to be actualised before costly do-overs become necessary. Using BIM for historic buildings is as pertinent as it is for new buildings.

Read more about how BIM technology has benefited our client in the Anstey Hall project on our blog.



Tuesday 24 May 2016

The Housing and Planning Act 2016, the Right to Build register and how authorities MUST give suitable planning permission for self-build

What’s the difference between the Self-build and Custom Housing act 2015 and the Housing and Planning Act 2016?

The Self-Build and Custom Housebuilding Act 2015 is a law that means since April 1st 2016, local authorities in parts of England are required to keep a register of people interested in building their own homes. This register is called the ‘Right to Build’ register.

Once the scale of demand for land is recognised, the local authorities are lawfully required to make council owned land available to those who registered, upon which to build a home. The homes must not be sold, rented or built as a holiday home, it must be the primary residence of the builder.

The Housing and Planning Bill has recently received Royal Assent, meaning this has also become law, this week in fact. The Housing and Planning Act 2016, is not the same as the Self Build and Custom Housebuilding Act 2015.

This latest act of Parliament includes the subheading, ‘Get the nation building homes faster’ and promises to;
  • unlock brownfield land to provide homes faster, requiring local authorities to prepare, maintain and publish local registers of specified land
  • support the doubling of the number of custom-built and self-built homes to 20,000 by 2020
  • ensure that every area has a local plan
  • reform the compulsory purchase process to make it clearer, fairer and faster
  • simplify and speed up neighbourhood planning

Planning permission for development applied for by those on the Right to Build register, must be granted, if deemed suitable, which could include self-build homes. To clarify, the permission is for planning, which could be improvements to existing properties, or new homes.

The Right to Build register – Facts as of May 13th 2016


  • Since the 1st April 2016, when the Self-Build and custom Housebuilding bill was passed, local authorities are required to open a register to compile a list of people (18yrs+ and British citizens or EEA/Switzerland nationals), interested in self-build
  • The Housing and Planning Act 2016 is now law and states that ‘an authority (to which this section applies), must give suitable development permission in respect of enough serviced plots of land to meet the demand for self-build and custom housebuilding in the authority’s area arising in each base period’
  • Councils in Wales, Scotland and Northern Ireland are not required to research demand in the way the rest of England is
  • You can register your interest in planning permission for development or self-build on The Local Self Build Register. Gemma Design would recommend you take advice from your local authority before registering.

The full details of the Housing and Planning Act 2016, including the definition of a suitable application can be found in this Government ‘bills’ document: http://www.publications.parliament.uk/pa/bills/cbill/2015-2016/0075/16075.pdf. Scroll down to page 14 for ‘Duty to grant planning permission’.

Further reading:





Thursday 24 March 2016

How BIM technology benefits clients – Part One: Saving time and money

Gemma Design have been appointed as the civil and structural engineering consultants for the restoration of 18th century barns that form part of the historic grounds of Anstey Hall in Trumpington, Cambridge. The project involves the creation of 12 new bespoke dwellings, including the restoration of eight listed timber and brick barns with new independent internal mezzanine steel frames and new extensions along with four new build contemporary properties.


BIM, Structural Engineer, Oxfordshire

BIM technology for planning, design and build

The client’s aim is to make use of all available technology and processes in order to deliver the project as close to a full Level 2 project as possible. Many people within the construction industry have come across the use of BIM, but the majority of projects delivered are new-build and do not involve working with historic buildings and particularly timber frames.

The original planning and scheme design for the restoration of our clients’ barns were carried out in 2D by other consultants, but Hill Group took the decision to engage Gemma Design and David Miller Architects to take the project forward within a BIM environment based on their combined expertise in the field. Gemma Design is a forward thinking engineering practice embracing the challenges that working with existing buildings brings. Applying BIM technology to historic buildings is part of our commitment to early engagement of technology on all projects ensures a culture of co-operation and collaboration within our industry.

BIM for collaboration saves time

The first step for the design team was to get together to discuss the employer’s information requirements and put together a project BIM execution plan to ensure a consistent approach. BIM is designed to enable all those who interact with the building to optimise their input and create value from combined efforts. Virtual renovation of the barns will allow for the impact on the structural integrity of the building to be realised before physical construction, thereby reducing uncertainty, improving on-site safety and preventing costly physical changes or fixes.

BIM, Structural Engineer, Oxfordshire

Everyone was in agreement that we should follow PAS1192:2 for model and document naming and use the AEC UK BIM protocol for content naming. Using this method enabled the design team to incorporate the Uniclass2015 classification system into all content and ensured full collaboration across the team and other systems.

BIM for benefiting the client saves money

The benefit to the client of using BIM over traditional methods for planning is that the clash detection is streamlined, bringing incompatible construction and structural conflicts to light, allowing for fixes to made at the desk and the project to run smoothly once it is under way.  The time taken for measurements of materials and labour required to complete the project is also vastly reduced.

In the next part of this series we will explain how the BIM process is bringing convincing benefits to the new build element of the Anstey Hall development, as well as the historic buildings.


Thursday 21 January 2016

What is a full structural survey?

Most commonly used as a means of inspecting all visible and accessible parts of your building’s structure, a full structural survey looks for defects within the structure and for possible future indications of defects and makes advisory notes for minimising both damage and the risk of future damage.
The full structural survey also inspects elements that do not make up the building’s structure itself, such as roof coverings like thatch and tiles, windows and drains.

When do I need a structural survey?

Here are four of many reasons for getting a full structural survey on a property.
1.      Before purchasing a house
Although it is not a legal requirement to have a full structural survey done on a property you’re hoping to buy, it is highly advisable. Once your offer has been accepted, your mortgage advisor is likely to instruct a survey to back up the financial offer. The vendor is also free to have a survey done on the property they are selling and make it available to all who ask. The buyer should consider getting the survey done by a chartered surveyor (MRICS) who will also look at issues with moisture penetration (damp), electrics etc that might not be structural issues but will affect the habitability of the dwelling.  The surveyor will advise if there are any issues that need to be investigated by a structural engineer.

Structural-Surveys-Gemma-Design


2.      Advice on building repairs after fire or flood damage
Bear in mind that fire damage almost always comes along with water damage from the effects of fighting the fire. So, whether from fire or water damage including external flooding due to adverse weather, or internal flooding from the likes of broken pipes, your structural engineer will assess the level of damage that has been caused. You will receive a full report detailing the integrity of load bearing structures within the building and advice on the extent to which repairs should be undertaken. Your structural engineer can also report on the risks associated with local flooding and subsistence. A good, comprehensive survey will take into account size and number of trees present, for example and offer advice on interventions such as underpinning. 

3.      Emerging structural issues
A substantial part of the work of structural engineers is assessing the defects that appear in buildings after the passage of time. Cracks in walls are very common as are areas of movement under floors and to the roof line. The causes of structural issues are fully investigated and appropriate solutions determined. Reports will include advice on repairs or changes to satisfy building control, local authorities or potential buyers.

4.      Before alterations
Prior to altering the size of your home, an inspection may be required to make viability calculations and ensure the adequacy of the existing structure. Structural advice, including drawings may be required by the local authorities before improvements or alterations are made to an existing building. Extensions into the roof for example will need preparations allowing for changes to the existing roof structures such as trusses, ceilings and floors below.


There are of course other reasons a full structural survey may be required, so if you require advice on any of the following, or on making applications for planning approval, please get in touch and we will be happy to discuss your requirements.
·        Advice on the preservation and/or repair of a building including listed buildings

·        Satisfying the requirements of the local authorities in terms of dangerous structure notices

·        Preparing plans for contemplated party wall agreements.

·        Structural appraisals of existing buildings that are being considered for change of use.

You can read about our structural survey services here: http://www.gemma-design.co.uk/inspections-surveys.html








 [RS1]Flooding and subsidence aren’t necessarily linked. They can be in the case of collapse inundation settlement but subsidence can also be caused by swallow holes, presence of trees etc.