Think Blog

Basement Conversions: from the Structural Waterproofing Consultants view

Master LogoTHINK BASEMENT specialises in basement conversions in the private residential sector, offering amazing transformations to existing underground spaces.

When visiting potential clients at home we get asked many questions regarding the method of waterproofing that we might use to protect their awesome new basement conversion from the ingress of water and moisture.

Keen to answer some of the most common questions, THINK BASEMENT has teamed up with Mike Vernon, a structural waterproofing consultant with DELTA membranes, to offer some great guidance on what you need to know about some of the best waterproofing methods available.Delta

Why is my basement damp?

Dampness in basements is usually caused by hydrostatic pressure in the ground, which means the pressure of water in the ground coming to bear upon the basement walls and floor. Dampness can also be caused by condensation. Unconverted basements rarely benefit from adequate heating and ventilation so “stale” cool moisture laden air comes into contact with cold surfaces causing condensation on them.

How can I stop the moisture entering my basement?

There are two main systems which are designed to stop water ingress into basements. Delta Type A systems are barrier systems which key to the structure, designed to block water out forever. Delta Type C systems (Known as cavity drainage systems) are dimpled membranes applied to the internal face of the structure where the aim is to manage and control water behind the membranes, diverting it to a Delta Dual V3 sump and pump system with high water alarm and battery backup.

What are the benefits of each system?

Delta blogDelta Type A barrier systems are generally more appropriate for new build schemes where they can be applied externally. This means they are pushed onto the structure by water pressure. However, once back filled it is difficult to access them for repair or maintenance. Where Type A systems are installed on the internal face, the “key” they form with the structure is vital, so the structure needs to be of very high quality and mechanical strength, otherwise failure will result. There is a very high emphasis on “perfect” workmanship and no penetrations are allowed because of the premise that the system is constantly resisting pressure.

Delta Type C cavity drainage systems rely upon the structure slowing down water ingress to a manageable level and dealing with water as it comes through by controlling and draining it away. Delta also specialises in Type A Delta blog 2products designed to improve the integral water resistance of the structure. The Delta system is inherently safer because the Delta “System 500”membranes are point fixed using sealed Delta plugs, can cope with movement, penetrations, and the quality of the substrate is not so important. Type C systems rely on gravity drainage or sump pump systems. Delta Sump pumps are highly developed, reliable and safe, with additional features such as Delta Dual V3 pumps, UPS battery backup units, high water alarms and textmax remote notification systems.

What to consider when thinking about my conversion?

Firstly, you need to consider what type of waterproofing system will be safest, because everything you put into the basement, including services, finishes, fixtures and fittings will need to be kept dry. Delta Type C cavity drainage systems are usually better for domestic basement conversions because they are very versatile and finely tuned and less reliance is placed on the quality of the existing substrates because cavity drainage membranes do not need to chemically “key” to them. Give consideration to using Delta Type A cementitious products such as Delta Koster Repair Mortar Plus and Delta Koster NB1 Grey in depth crystalline slurry in terms of localised measures to improve the integral water resistance of the structure first.

It is important that suitable environmental controls (heating and ventilation) are designed and installed to avoid issues with condensation. A specialist basement conversion company such as THINK BASEMENT can advise you on these.

If you are seeking Building Regulations Approval, your Local Authority will be able to advise on considerations such as fire regulations, means of escape, conservation of energy requirements, acoustic issues etc. It is a good idea to seek an informal meeting with your Building Control Officer first, prior to making submissions, in order to seek an opinion regarding what your Local Authority would like to see.

What to look for when choosing a contractor?

Look for a specialist basement contractor who specialises in the installation of Delta systems. There are industry specific qualifications too, which the contractor may hold or may be in the process of attaining. Delta products and technical backup are second to none, so you may be assured you are in safe hands when choosing a Delta system.

What to ask a potential contractor?

  • Do you specialize in Delta systems?
  • What industry specific qualifications do you hold?

What impact on my designs might waterproofing systems have?

Delta systems are completely compatible with installation of internal finishes and services. Delta Membrane Systems Limited have scrupulously developed these and perfected them over time, so they are complimentary to both a variety of structures and allow you complete freedom to choose the fixtures and fittings to give you the basement of your dreams.

THINK BASEMENT and DELTA MEMBRANES are happy to be working together to provide you with all of the information that you will need regarding your basement conversion project. As part of the design process for your basement conversion, specific specialist attention will be given to the design of your structural waterproofing system to ensure that your basement remains a dry and pleasant environment. DELTA consultants will even visit your basement project to ensure that the fitting of their products are to the highest standard, giving you extra peace of mind. All of the technical specifications for DELTA products can be found on their website or provided by THINK BASEMENT during your design phase.

You can find THINK BASEMENT online: or contact us: or 01142 583500.

You can find DELTA membranes online: or contact us: or 01992 523 523.

Read More
Basement Conversions – from a Structural Engineers View

Logo smallTHINK BASEMENT specialises in basement conversions in the private residential sector, offering amazing transformations to existing underground spaces.

We get many enquiries from homeowners keen to take advantage of the fantastic potential that their basement offers, but who may be worried about the structural effects that a conversion could have on the rest of their property.

Signature structures Logo

Keen to dispel some myths and answer some of the most common concerns, THINK BASEMENT has teamed up with Dean Miller, Structural Engineer and founder of Signature Structures, to offer some valuable information to those thinking about undertaking a basement project.

My basement has very low ceilings, what does ‘digging down’ entail?

Knowing the nature of the ground beneath the existing floor and foundations is fundamental to a basement conversion involving excavating. Naturally, if the ground is extremely hard e.g. sandstone / limestone then excavating will be more intensive than for clay or sandy ground. Digging trial holes is a vital method to establish the existing ground conditions and foundation depths. This should be carried out well before any works commence on site and forms part of a ground investigation report which an engineer would carry out.

Excavation requires good access or a practical method for debris removal by the contractor, as there can be sizeable amounts of material to take away from site via skips or other means.

A common error on sites without proper design work can be excavating the ground to a depth which provides insufficient head-height. Signature Structures works with Think Basement and the Architect to ensure that the correct head-height is achieved.

I can stand up in my basement, but the floor is damp. What can be done?

If adequate headroom exists currently, then you may want to ensure that the area is properly damp-proofed and insulated. The design team would specify the means of damp-proofing for the floor and walls in contact with the external ground. We would work with Think Basement to ensure that no break lines occur across this layer, as this would totally defeat the purpose of the damp-proofing installation.

Will my house need underpinning? What does this mean?

Underpinning means deepening of foundations. This can be necessary for basement conversions to allow for the desired head-height. Often the depth of a new concrete slab, insulation and floor finishes can lead to excavating for the underpinning of the walls and also the existing floor. A good engineer will detail the sequence for underpinning, striking a balance between not removing too much or too little ground at intervals e.g. one would not remove all of the ground beneath a wall in one go, as this would create an unstable wall.

Will structural work on my basement affect the rest of my house?

Without sounding too alarming, some form of settlement will occur if underpinning is carried out, as the existing building will be supported off a new foundation layer. This settlement may be a few millimetres but can lead to visible cracks in walls at the floor above. This is to be expected especially with plaster finished walls or tiled areas. This should not be a long-term occurrence and an allowance for the repair of these cracked areas should form part of the works.

Do I have to inform my neighbours of the intended work?

The owner of a terraced or semi-detached building undergoing underpinning will need to notify their neighbours of the proposed works. The underpinned party wall will after all be theirs also, so they will need to be kept in the loop. We advise to maintain a dialogue with the neighbour from the offset. A party wall notice can be served whereby all details and proposals are submitted to the neighbour. Always communicate with your neighbour, as the converse can cause friction and in some cases objections to works being carried out.

It is the duty of all involved to safe-guard the well-being of those carrying out the excavation works, as the basement of the property poses a large degree of risk to those on site without proper details.


I have walls dividing my basement into separate rooms, do these need to be supported?

When excavating adjacent to internal partitions, which tend to be brick, care needs to be taken not to rely on a sliver of ground to support the wall during the process. A large number of stoppages and abortive works concerning basement conversion can be down to the lack of satisfactory support for the internal partitions during the excavation works. During works, sites can get water-logged and so a worst case scenario would be the collapse of a partition resulting from insufficient ground beneath it. We detail a method from the outset to avoid this regrettable scenario.

What affect does a structural engineers report have on a building inspector approving the works upon completion?images

In addition to the ground investigation report, an engineer should provide structural calculations and drawings for the proposed work. These structural details are submitted to building control for approval. Whilst works are on site, the construction is checked against these details. If the two match then the owner is awarded an approval certificate. Make no mistake about it, this certificate is extremely important as it verifies that the works were carried out satisfactorily and that the end result is safe for living. In future when it comes to selling your property, the difference between having and not having this certificate is vast. The solicitor for the purchaser would point out if these works were not approved, if so, they cannot be deemed satisfactory or even in some instances – safe.

Clarity is vital for informing the contractor of the proposal, so we have evolved our drawings over recent years to achieve such clarity.

What if I need steel support beams installed?

If any partitions are to be removed in the proposed scheme, these can often be difficult to get into the basement in one length. An engineer can provide details so that a beam can arrive at site in sections and then bolted into the finished length on site.

Steel reinforcement is often required either in the new ground slab, underpinning or both. British standards and Eurocodes give guidance of how much gap (cover) to provide between the edge of the concrete and the reinforcement. An engineer should be proficient in specifying such detailing. Relying on the judgment of an untrained person can result in steelwork with insufficient cover and therefore increase the risk of corrosion. Remedial works to combat corrosion of steel reinforcement can be very expensive.

Up or Down?

Loft conversions have been very popular over the past few decades. We believe basement conversions, with the correct design & build team, can be just as popular if not more so. Choose Think Basement to get your conversion to the finish line!

You can find THINK BASEMENT online: or contact us: or 01142 583500.

You can find Signature Structures online: or contact us: or 0114 3450381.


Read More
Basement Conversions – from the Chartered Surveyors view

Home owners, Landlords and Letting agents…Would you like to increase rental yield or the value of your property?

Are you prepared for the 2016 change in energy efficiency and the private rented sector, does your basement comply with Building Regulations?


Basement conversions – Much more than just a luxury!

Logo smallTHINK BASEMENT specialises in basement conversions in the private residential sector, offering amazing transformations to existing underground spaces.

In addition to the aesthetic benefits, converting a basement level will provide significant improvements to the internal environment of the entire house! THINK BASEMENT has partnered with Mike Kidder, Chartered Surveyor, to investigate the impact that a basement conversion can have.

In many houses, unconverted basements are usually cold, damp spaces that could allow moisture and draughts to penetrate other parts of the house and create problems with condensation. Cold air circulating beneath the floorboards of ground floor living spaces will also result in potential heat loss and will reduce the thermal efficiency of the building as a whole.IMG_4508

In the past homeowners have tried to solve these problems by blocking up ventilation grates and redundant coal chutes in the belief that this would help prevent cold air and moisture entering the cellars. In reality this often makes the situation worse by stopping the flow of air and trapping moisture in the sub floor areas, leading to problems with timber decay and expensive repair bills dealing with conditions like Dry Rot.

By tackling damp and poorly vented cellars a number of potentially damaging and harmful issues, such as natural build concentrations of radon gas and timber decay, can be resolved. The British Property Federation recommends maintaining your property in good repair:


‘It is essential that damp and damaged building elements are tackled before or alongside energy efficiency improvements. A damp wall will transmit heat out of the building more readily than a dry wall, and could cause structural problems and health issues for tenants’.

Mike Kidder says: ‘Basement conversions are very useful and beneficial at all of the different levels of treatment from the basic floor replacement and improved ventilation for storage areas, to the full blown tanked and sealed rooms that can be used for additional living rooms. Most people do not realise that these rooms can be converted and consequently they get overlooked, or people think that the costs outweigh the benefits’. In most cases the cellars are the same floor area as a lounge or dining room and could provide a considerable amount of extra space within a terraced house for more beneficial use.

One of the aspects of a condition report undertaken by a chartered surveyor is to assess whether the work that has been undertaken on a basement conversion meets the associated Building Regulations and is classed as safe for habitation.

With the potential in an existing basement to increase a properties living accommodation by up to 50%, and the vast majority of cases requiring no planning permission and offering minimal disruption during the works, many property owners are deciding to investigate how they can turn their basements into the spaces that they need, with the features that they desire.

 ‘I would estimate that in Sheffield and the surrounding areas, only 10-15% of basements have been converted, with around only 2% of these complying with Building Regulations’

– Mike Kidder

THINK BASEMENT has seen an increase in enquiries from Landlords and Letting agents who are looking to increase their rental yield and get a great return on investment by converting their basements into additional residential accommodation. This is often in properties that have no scope to extend the house in any other way, because of site limitations. In the case of rented properties, the potential economic benefits can be significant. Properties in Sheffield, in the S10, S11 and S6 postcodes indicate that a double room in a rented house can command a rental value of between £55.00 to £65.00 per week. An investment of £15,000 to create a double bedroom (most likely with en-suite) at basement level could be recouped within 4 to 6 years.

In addition by converting a basement, the energy efficiency of a property can be upgraded as a parallel benefit. The briefing document regarding the forthcoming change 2016 in regulations entitled ‘Energy Efficiency and the Private Rented Sector’ states that under the Energy Act 2011, the government will be introducing new requirements for every property offering rented accommodation, both private and subsequently commercial, to meet a minimum level of energy performance.

A basement conversion undertaken by THINK BASEMENT will  meet the required Building Regulations regarding habitation, and as a matter of course will include the following measures to address energy performance:028

  • Installation of a water proofed and thermally insulated concrete floor
  • Management of damp and moisture away from the structure of the building
  • Installation of solid wall insulation
  • Insulation of ground floor services, such as central heating and hot water pipes to reduce boiler demand and therefore reduce energy consumption
  • Installation of suspended timber floor (between joist) thermal insulation
  • Installation of active air ventilation systems ensuring removal of any excessively moist air from the internal environment
  • Installation of low energy consumption lighting and water maintenance systems
  • Installation of high-performance double or triple glazed windows and/or doors
  • Option to replace and upgrade existing central heating systems

In addition to the above features in every conversion, THINK BASEMENT are able to offer services that can be applied to any part of the property:Membrane

  • Installation of internal Solid Wall Insulation (InSWI)
  • Installation of External Solid Wall Insulation (ExSWI)
  • Installation of Solid or Suspended floor insulation
  • Installation of damp-proof measures including Direct Injection, Cavity drained membranes and Cementitious (Render-based) waterproofing.

Internal Solid wall insulation can be fitted on a room by room or whole property basis, often undertaken in conjunction with decorative upgrading or refurbishment of bathrooms or kitchens. Internal SWI will generally cost less than External SWI to install, however External SWI is thought to have marginally better thermal insulation properties. A combined system approach to improving energy performance can be taken, ensuring damp in walls is addressed before the installation of thermal insulation, thereby maximising efficiency. The aesthetic impact of External SWI may be a consideration and can be limited by installing only to rear or less visible walls, whilst applying Internal SWI to the front or outwardly visible parts of the property.

epcsAll of the measures above form part of the recommendations that appear on the Energy Performance Certificates (EPCs) that every property must have at the point of sale or rental. The benefits of specifying these features during a basement conversion includes likely low levels of disruption to the rest of the property and the ability for building inspectors and surveyors to work with THINK BASEMENT and record every part of the installation process. The opportunity to incorporate cutting edge technologies and renewable energy sources is tremendous during a THINK BASEMENT project…why not consider installing ground or air source heat pumps, biomass boilers or even take the opportunity to incorporate the infrastructure for solar panels or wind turbines into your property, the basement offers and excellent location for the management systems needed for these systems!

The importance of energy efficiency in the private rented sector is likely to grow over the next few years. New regulation, in particular plans to provide tenants with a right to request energy efficiency improvements from April 2016 and to make it illegal to let energy inefficient property as determined by the EPC from April 2018, are likely to have a significant impact on the sector. However energy efficiency is not just about getting ready for legislation, it can offer Landlords and home owners a fantastic opportunity to upgrade and improve their properties and maximise the value of their investments.

What should you do NOW?mike-kidder

The partnership between Mike Kidder Associates Ltd and THINK BASEMENT provides you with the ability to determine which scheme would be best suited to meet your particular requirements for a basement conversion. A survey will advise on the condition of the existing cellar/basement and recommend what improvements could be undertaken. A valuation could be provided to enable you to see the difference in the Market Value of your property with the works completed, further enabling you to make the correct decision on which type of scheme to opt for. If you think that your basement would benefit from being improved then please use the contact details below:

You can find THINK BASEMENT online: or contact us: or 01142583500.

You can find Mike Kidder Associates online: or contact us: or 01143215081.


Think-Basement-Logo mikekidderassociateslimited-sheffield-0


Read More
Basement Conversions: from an Architects view

Logo smallTHINK BASEMENT specialises in basement conversions in the private residential sector, offering amazing transformations to existing underground spaces.

For many basement conversion projects, our clients have fantastic ideas about what features and requirements their new space should have. In order to help turn these dreams into reality, THINK BASEMENT has partnered with Mike Leigh, Architect and founder of Time Architects,Time Architects Logo to offer a project design and delivery service that is second to none. Mike is keen to give his perspective of the processes involved in creating truly superb basements and the benefits in using professional design teams for your project…

When considering a basement conversion within your home, as with many things in life, it pays to create a well thought out plan. The starting point of any plan is to identify the ultimate goal – the problem to be solved. Most clients I meet when looking at domestic projects of any type simply state “I need X number of Bedrooms/ Bathrooms etc. and this is where I want to locate them”. However, with a basement conversion you are ultimately starting with a set of constraints i.e. the footprint of the space, the available head height, sources of natural daylight and ventilation, connectivity to the garden area, structural materials, the location of an access stair to suit the floor plan above, the location of existing services supply and drainage and the existing ground conditions. With these points in mind the space available then ought to point the architect in the direction of a logical solution in terms of space design, and this of course needs to be married to the needs of the client.


Budget is obviously a big factor in most conversions and the architect should take a ‘whole house’ approach looking at the rational of the existing floors primarily. All of the above points can be overcome where required, but each remedial action carries with it an associated cost which can eat into the budget. A good architect will be mindful of this and will look to generate a proposal that meets the client’s needs, offers best value for money and also offers that wow factor that separates a great project from a good one. With this in mind then, it pays to employ an architect as soon as possible, arm them from the off with your problems to be solved and dreams and visions rather than possible solutions, identify your budget and work closely together to achieve the best possible solution for you and your home.

So what things can you do with your basement? And what should you spend your money on to get the best results? Two very important questions both of which are fully dependent on the individual case at hand and clients themselves.

We are all individual different people with specific interests and needs and each live in a space that we mould to suit our lives. Traditionally kitchens, bedrooms and bathrooms are the spaces thought to be able to add value to a property. It is important to understand though what we mean by value. In monetary terms outside of certain key development areas (such as London) it is unlikely any such work will increase the value of the property beyond that of the cost of the works themselves. Also as most estate agents will testify, a property is likely to be constrained by a ceiling purchase price determined by the relative value of other local properties and the desirability of the area of its location. However a well presented property, with good and efficient use of internal space, clear links to good useable outside space and well accommodated and apportioned spaces, ought to be considered as desirable if and when looking to sell the property.

Above and beyond kitchens, bedrooms and bathrooms it is becoming more desirable to create leisure and entertainment spaces within the family home and a basement conversion offers an ideal opportunity. These can include formal kitchen and dining rooms, a library, children’s play spaces, a cinema room, a swimming pool, sauna/ steam rooms, a bar and social space, a computer games room, a garden room or indeed whatever suits you and your life.29 Strelley Ave S8 Existing Basement 3D

Whatever you decide is right for you, a basement conversion is always likely to be a good value investment in your property if planned properly and thoughtfully to suit you and your needs. It is likely to be a simple process to achieve planning consent and in most cases will give better access to, and  relationship with, your garden space. In relative terms a basement conversion is the type of expansion project that will have the least visual impact on your home externally and therefore from the point of view of neighbours will be the least intrusive.

THINK BASEMENT and Time Architects have developed a professional partnership that aims to go beyond the often compartmentalised professional roles that can be found on building projects. Time Architects extensive experience in dealing with highly sensitive and complicated heritage projects around the UK has highlighted the need for a great degree of collaboration and shared vision between architect and building contractor. This ethos is easily demonstrated when conducting joint site visits to proposed basement conversions from the very beginning of the project. Establishing a fantastic dialogue between the client, the architect and the contractor is essential to ensure that the journey from the clients first ‘wish-list’ to the completion of the project is as smooth and positive as possible for all involved. Not all basement conversions require significant input from the architect, but Mike and the THINK BASEMENT team will often be found sharing a coffee and discussing projects that are in the planning stages, ensuring that each prospective client can be sure that they are getting the best possible advice, guidance and service for their home.

If you are considering a basement conversion, or would like to chat about any ideas you may have, THINK BASEMENT and Time Architects are happy to help.

You can find THINK BASEMENT online: or contact us: or 01142583500.

You can find Time Architects online: or contact us: or 0114 285 4554.

Read More


A Winning Combination

Logo small

THINK BASEMENT is a proud member of the hottest networking group for the construction industry, THE TRADES HUB!

THE TRADES HUB offers members the chance to network with like-minded people from all aspects of the industry and gives access to a full range of business support services such as business coaching and mentoring through the networking groups, Marketing and Branding with TRADES HUB MARKETING, Insurance and Financial support through TRADES HUB PROTECT and much more!

The Trades Hub logo

During the recent relaunch and re-branding of THINK BASEMENT, we were able to take advantage of a wide range of the support offered. Initial guidance on drawing up business plans and setting goals, as well as how to ensure that our branding reflected the company that we wanted to grow. Working closely with James Ashford, Marketing director, we built a website and company brand that we were proud of and applied the brand to all of our company resources!

See what we thought of the whole process here: THINK BASEMENT @ THE TRADES HUB

We have successfully relaunched THINK BASEMENT as the best Basement Conversion company in the region, and we are able to spread the word through the fantastic network of colleagues that we have through our membership with THE TRADES HUB. Being surrounded by individuals that share our passion for our companies, and who are committed to offering the best service to our customers every time, we have forged relationships that will mean more amazing basement conversions will be taking place near YOU!

THE TRADES HUB offers support and advice to all construction trades, regardless if you are active networking members, if you need an objective review of your website or a chat about where you want to take your business, check out their website:

Read More
Going Underground…

Basement conversions: The new underground movement.


At THINK BASEMENT we’re passionate about helping you improve your quality of living. Whether you want a comfortable, cosy living space, or a luxury, high-spec entertainment room, we’ll help you create something simply fantastic!

We’ve all heard about the housing crisis in the UK, not enough new homes being built, average house prices rocketing way beyond comparative average earnings and a mortgage drought unless you can produce a hefty 40% deposit!

As a result of this many UK homeowners are opting to extend their homes and there is an increasing desire among property owners to make use of previously uninhabitable basement space.

Why should you convert your basement into a fantastic living space?  Steve Hodgson, Chief Executive Officer of the Property Care Association said: “Basement conversions provide meaningful and useful space, transforming previously uninhabitable damp basements into an attractive and dry area suitable for a number of uses, such as an indoor gym, office, additional bedroom, dining area or even for storage.”

Read More
Welcome to our new website!

We would like to give you a very warm welcome to THINK BASEMENT. We are a brand new company in Sheffield who are passionate about helping you improve your quality of living by transforming your unused basement.

Whether you want a comfortable, cosy living space, or a luxury, high-spec entertainment room, we’ll help you create something simply fantastic! Find out more about us >>

Please have a look around our website, especially checking out some of our recent projects and our page dedicated to giving you some ideas for your very own basement conversion!

Keep an eye on this blog too, to see updates from Think Basement.

Read More