Polished concrete floorıng

A great way to bring a stylish contemporary aesthetic to your home — read on to find out more about this versatile and hardwearing flooring option.

Polished concrete is not just a material used by those after a super-contemporary industrial look — new techniques and finishes means it’s now being used by those after all kinds of interior schemes, looking for a sleek, easy-to-care-for floor.

Polished concrete comes in a variety of colours and finishes and is perfect for use with underfloor heating, too — as well as being a good retainer of heat. Polished concrete flooring is achieved using concrete – cement, gravel, sand and water – with chemical densifiers added to it. These densifiers act to fill the holes and pores in the concrete. The poured concrete is then ground down with diamond polishing tools, which get progressively finer until the level of sheen and smoothness you are after is achieved. And despite some common misconceptions, it need not look or feel cold.

ADVANTAGES

Polished concrete has a lot of benefits, including being:

● A smooth and sleek flooring type that suits the minimalist interiors of many contemporary homes.

● A low-maintenance, easy to clean flooring. This flooring is perfect for households with pets and in rooms with high levels of foot traffic as it is extremely hard and durable and simple to keep clean.

● A non-slip finish. Despite its ‘sheen’, polished concrete is a non slip type of flooring, which makes it ideal for use in kitchens, bathrooms and utility rooms.

● A seamless look between inside and out. Polished concrete flooring is also suitable for exterior use so is ideal where a level threshold is required between indoor and outdoor spaces, for example where bifold or sliding doors have been incorporated into a design.

● Underfloor heating. Concrete is an excellent heat conductor and is easy to pour over an underfloor heating system.

● A floor that benefits from solar gain. In spaces where the sun is allowed to shine in, a polished concrete floor will absorb and hold the heat well; this is especially the case in south-facing rooms

You should be aware that polished concrete floors will occasionally require resealing. There are a range of stain-removal treatments and aftercare products available to keep your floor looking its best. “However, a polished concrete floor is designed to last a lifetime with very little maintenance required,” points out Ben Young of polished concrete specialists Lazenby.

COLOURS AND FINISHES

If you are looking for a bespoke look for your flooring, polished concrete can deliver — no two floors will look the same, thanks to the natural colouration and distinctive patterning found in each installation. Polished concrete floors suit contemporary interiors well, and can add a modern accent to more traditional designs, too. And by choosing a glossy polished finish, your flooring will look more like a stone tile.

“We have a range of 15 standard colours but bespoke colours matched to RAL numbers are also possible,” says Ben Young. “Every floor is available in a matt, satin or gloss finish depending on the level of sheen required. It is also possible to expose the natural aggregates within the concrete through diamond polishing.”

TYPICAL COSTS

As a guide, a new polished concrete floor, poured, finished and sealed, will cost around £120/m²-£150/m². If you have an existing concrete floor that you wish to have polished, the cost will be approximately £50/m².

There are several factors that will influence what you pay:

● the area you are in

● the quality of the existing floors (in renovations) and whether any repairs are necessary before work can begin

● the size of the house

● the type of finish you are opting for (those with exposed aggregate finishes will cost more).

If those prices are outside your budget, consider concrete-effect porcelain tiles that typically cost from £20/m².

INSTALLATION METHODS

The most common way for a domestic floor to be poured and finished is using the ‘flooded bay’ method. According to Ben Young, the largest area or ‘bay’ Lazenby can pour is 5m x 5m. For areas larger than this, inducement joints will be cut in the day after the floor has been poured, using a neat saw.

These joints will also be used in doorways. They create a weak spot, meaning the concrete will shrink and crack in a straight line. This joint can then be filled with a flexible sealer such as polyurethane in a similar colour to your floor.

● The ready-mix concrete will be poured on site, usually reinforced with steel mesh and fibres. This mesh is used to minimise the risk of the floor cracking. The concrete should be poured after insulation and underfloor heating has been put down to a depth of 100mm.

● The whole space is filled and levelled using a laser, rakes, vibratory screeding machines and bull floats. Once the surface has been screeded, colour, if required, is applied to the surface. Over the course of the day, the concrete surface is refined and flattened using hand floats and power floats.

● The final surface is closed off and densified by hand trowel and/ or power trowel machines. This brings the cement paste to the surface, smoothing and hardening it until it develops a sheen. This can take anywhere from four to 14 hours, and partly depends on the weather conditions: too cold (5°C or lower) and fresh concrete can be permanently damaged; too hot and there is a risk of the concrete shrinking.

● Once poured and prepared, the concrete will need to be polished and sealed — something that must be carried out at least a month after pouring.

● Polishing either comes from cleaning and buffing the floor with a scrubbing machine or, better still, light diamond polishing to remove minimal laitance to bring out a medium sheen. For highly polished floors, the surface can be further enhanced using diamondencrusted flexible buffing pads.

● The floor will then need to be sealed. A penetrative sealant that allows the concrete to breathe is used for this.

Some suppliers offer alternative, although less commonly used, methods of installation, for example where the finished floor is poured as a ground-bearing slab. These floors usually have a minimum thickness of 150mm and come with heavier reinforcement.

The floor is poured onto wellcompacted MOT Type One (an easily compacted aggregate), blinding sand, DPM (damp-proof membrane) and insulation. A polished screed already has the ground-bearing slab in place and is poured over the insulation sitting on the slab below.

The polished ground-bearing slab has the added advantage of producing the finish in one go, but will have to be poured earlier and may suffer damage as other heavier work is carried out afterwards.

SCHEDULING THE INSTALLATION

When building from scratch, or using polished concrete when building an extension, the majority of in-situ polished concrete flooring is put in place prior to doors and any door tracks that may be fitted.

It is possible to produce the floor with these elements in place, but there is a great risk because cement corrodes aluminium and the process is not a delicate one. Doors can also cause a hindrance to the contractor and do not allow for threshold details to be incorporated.

A 10mm-thick brick-foam material is fitted to the perimeter of the floor to allow for any movement. This needs to be hidden by skirting or similar, so the floor must be poured before this stage of decoration, too.

In the case of shadow gaps, recessing it behind the wall build-up will hide the expansion material, and the floor should then be poured before the final wall finishes are built out.

Any partition walls, kitchen units and other structures should ideally be constructed on top of the finished concrete floor.

It is not necessary for windows and external doors to be fitted prior to fitting, but the inside should be protected from the elements in extreme weather and cold.

INSTALLATION TIME

According to Ben Young, “a concrete floor will be installed in three days. This includes all setting up and the final protection layer.” The concrete must be left to cure sufficiently before the grinding (polishing) process can begin, which is 28 days, generally.

SOUNDPROOFING A CEILING

Soundproofing a ceiling can be key to your enjoyment of spending time in your home. And it’s not something that only applies to those living in flats, either — if you live in a terraced or semi-detached house you might also find yourself plagued by noisy neighbours or lodgers. Even those living in detached homes may have to endure noise transfer from upstairs (teenagers playing loud music or children running around, for example).

Here’s all you need to know about soundproofing a ceiling, no matter what types of ceiling or home you have.

Before you can find the right soundproofing and noise control solution for you, think about:

● The type of noise you are trying to stop

● The type of ceiling you have

● Whether the noise is coming from above or below

● How loud the noise is.

Once you’ve answered these, you’ll be better placed to understand the options available and how they can solve the issue. And for soundproofing to work well, the right systems must be selected and it’s crucial they are fitted correctly. Ian Baker from The Soundproofing Store agrees: “Soundproofing is just like waterproofing — it’s only as good as its weakest point. Think of a car window. Even if it’s open just a tiny bit, you get all the noise from outside coming in.”

DIFFERENT KINDS OF NOISE

Firstly, it’s important to ascertain the kind of sound you are faced

with. “There are two types of sound that need to be dealt with when it comes to soundproofing a ceiling: airborne and impact,” explains Ian Baker.

“Airborne is the type of noise created by talking and sound of the television, for example. Impact noise, on the other hand, is caused by footfall, such as people running or walking around or items being dropped.”

The soundproofing measures required to stop the transfer of these different types of noise are not the same.

“To prevent airborne sounds you need to add extra mass to the ceiling, while to reduce impact noise you need a dampening system to absorb the vibrations,” explains Ian.

“The higher the decibel (dB) figure for airborne noise, the better, while the lower dB figure for impact noise the better. It’s usually necessary to address both airborne and impact noises.

TYPES OF CEILING

Your next consideration should be the type of ceiling you have: timber joist or concrete. “Concrete ceilings tend to have a high level of mass and density, which should already reduce a good level of airborne sound,” begins Mike Cunningham from Noisestop Systems. “With concrete ceilings, impact sounds will transmit through this material. Timber ceilings that have not been soundproofed often have both impact and airborne sound transfer between floors.”

Although the solutions for each type of ceiling are different, in general, there are three main aspects to soundproofing: adding mass, incorporating a material to absorb sounds, and creating separation.

● Mass: The higher the mass, the more you will reduce airborne sound. High-mass products such as acoustic insulation, soundproof plasterboard and mass-loaded vinyl will significantly reduce airborne sound.

● Absorption: This refers to the ability of the ceiling to absorb sound. Acoustic insulation between ceiling joists will help absorb sound as it transfers between floors. Empty ceiling cavities will often act as a drum, and the sound will resonate inside the cavity and amplify the sound.

● Isolation/separation: Creating isolation within the structure of the ceiling will reduce vibration. As the impact and airborne sounds transmit through solid surfaces via the vibration, it is essential to isolate the existing ceiling from the new soundproof ceiling.

TIMBER CEILINGS

In general, the approach to soundproofing a timber ceiling involves a combination of insulation, metal rubberised clips to absorb vibrations, metal channels or battens, and perhaps vinyl or rubber panels and a couple of layers of acoustic grade plasterboard. “The majority of our clients have timber joist ceilings,” says Ian Baker. “When we soundproof timber ceilings we need to create a sealed chamber which will absorb vibrations.

“First we add acoustic mineral wool insulation. Once the insulation is in place, metal rubberised clips are attached to the bottom of the joists, before ‘furring bars’ or ‘furring channels’ (metal battens) are fixed to them to take the new plasterboard.

“Next you need to add mass to deal with the airborne noise. We use two layers of acousticgrade plasterboard, using a rubber sheeting, called TecSound, between them. The aim is to use a combination of several high-mass materials for the best results — rather than lots of the same layers. Using this kind of system, you can expect to lose around 60mm of ceiling height, but you should get a 75% reduction in noise.”

CONCRETE CEILINGS

Here a different approach is required. “Because concrete ceilings already have high levels of mass, it is customary to treat these ceilings for impact sounds from above,” says Mike Cunningham.

“However, if you have plenty of height in the room, you could consider installing an independent ceiling. This type of ceiling does not touch the original and requires new ceiling joists. It does not require too many specialist products as the ceiling being independent is the key element.”

However, the most common method of soundproofing a concrete ceiling without losing head height is to use a system of products fixed directly to the concrete ceiling. “In an ideal  world, a new suspended frame would be built below the concrete ceiling to decouple it from the original structure,” says Ian Baker. “Our standard specification is to use our ReductoClip system directly to the concrete ceiling, resulting in only a 60mm loss of space. Mineral wool is also added in between the first layer of plasterboard and the original concrete ceiling, to stop any sound from amplifying within this space.”

When soundproofing a concrete ceiling to block out noisy neighbours, the sound can also travel down the walls so it is worth doing an ear test, listening for any noise coming through the walls. If this is the case, then soundproofing the wall will also be required.

THE CEILING LIGHT EFFECT

So does having ceiling lights affect soundproofing? “Think of sound like water in a bath — if you pull the plug out, all the water escapes,” explains Mike Cunningham. “Sound works in a similar way; if you leave even a small hole or gap, it will compromise the level of soundproofing.”

For this reason, you want to avoid cutting any holes in your ceiling to take new lights. Surfacemounted spotlights or pendants are a better option where sound travel is an issue.

THE COST FACTOR

This will largely depend on the size and type of your existing ceiling, and your approach. Based on a ceiling size of 4m x 4m, using a product such as the ReductoClip ceiling system, materials would cost around $1,800 - $2,000,

Another factor is whether you choose to do the work yourself. Many soundproofing kits can be fitted by a competent DIYer — but some of the elements are very heavy and so this is a job for two people.

Alternatively, you’ll find most soundproofing specialists will have a list of trusted installers.

14 Things to know about roof structures

Selecting the right type of wall construction is one of the most important stages in the design of any self-build or home extension project. Yet when it comes to roofs, the decision-making process rarely extends much beyond the choice of tiles or slates.

Roofs are one of the most complex, aesthetically critical and potentially troublesome parts of the build, so it’s a little worrying that more time is often devoted to choosing kitchen units than making sure the roof is fit for purpose. Here are the top 14 things you need to know before putting that roof over your head…

1. Roof design factors

Picking the right ‘hat’ for your building will depend in large measure on what it’s sitting on. The layout of the rooms below and whether the roof needs to span across large open spaces without interruption will be key to the design of the roof structure.

As well as resisting everything the elements can throw at them, roofs also need to look right. Steeper roof slopes are normally required to accommodate habitable attic rooms, although there may be planning restrictions on height to contend with. How steep or shallow the roof is will also have a bearing on your choice of coverings, which need to be technically compatible with the degree of slope.

Once you’ve got an outline roof design, a structural engineer will need to be consulted on how best to achieve this in practice. This task will be a lot more straightforward where roofs are sitting on a simple oblong box without multiple corners or complex level changes. Engineer’s calculations will need to be produced to factor in all predicted loadings including ‘dead’ loads (from the building itself ), ‘imposed’ or ‘live’ loads (from occupants and contents), and those from wind, snow and so on. 

2. Trad vs. modern?

Until the late 1960s, most roofs were constructed in time-honoured fashion by chippies cutting and joining lengths of timber on site. But with the advent of labour-saving prefabricated trussed rafters, traditional ‘cut timber’ roofs were largely superseded in volume housebuilding. In the 1990s, technology once again moved on with the introduction of pre-insulated manufactured roof panels which promised to save even more time on site. Today any of these options, or some combination, could potentially achieve the optimum roofing solution, depending on what best suits the style and function of the building.

3. Cut timber

The blueprint for a standard ‘cut timber’ roof is fairly straightforward. The main roof slopes are formed from a series of rafters cut from standard lengths of timber (traditionally 4x2 inch). In dual pitched roofs the rafters are propped up against each other to form a triangle, with a long length of timber known as a ridge board running along the full length at the apex. Each roof slope is normally given extra support underneath around mid-span typically in the form of thick horizontal timbers known as ‘purlins’, which may need to be supported by struts resting on load-bearing internal walls.

4. Prefabricated trusses

Unlike custom-made traditional roofs, prefabricated triangular trusses are delivered ‘oven ready’ to site and simply need to be positioned in series to form a basic roof structure. Despite the comparative thinness of their timber component parts, a lot of strength is derived from the overall integrity of the structure, typically with distinctive ‘W’ shaped webbing in the centre. The bottom ‘chord’ of the triangle doubles as ready-made ceiling joints with no need for support from purlins, struts and so on.

5. Panelised roofs

Panelised roofs are prefabricated roof slopes delivered to site ready to be craned into position. They are mostly made from thick SIPs (structural insulated panels) comprising two sheets of plywood or OSB with a filling of insulation sandwiched in between. The panels are hoisted onto a prepared supporting framework at ridge, wall level and sometimes also at mid span. 

6. Best roof for quick install and wide span

Take a look around any large residential construction site and the chances are you’ll see lorryloads of trussed rafters awaiting installation. This type of roof structure is still the number-one choice for mass-produced ‘box’ homes. The appeal of manufactured trusses is that they’re much quicker to install on site than the handmade variety; a basic roof structure can be built in a day. Also, because they can span eight metres or more from wall to wall there’s no need for internal load-bearing ‘spine walls’. And because trusses are spaced further apart (600mm centres) than conventional rafters they use less timber than traditional roofs.

Their main drawback is obvious to anyone who’s ever popped their head into a loft — the forest of timber webbing is a major impediment to movement within roof spaces. And because the timber components are so thin it makes them difficult to alter or customise. Today, a number of variations are manufactured for different house styles, but with less advantage in terms of cost and build speed. ‘Attic trusses’ are a popular modern variation with an open centre for attic rooms or subsequent conversion. Trussed rafters are ideal for multiple housing with relatively simple house designs and suitable lifting/handling equipment on site.

7. Best roof for bespoke designs

Traditional hand-cut timber roof structures are ideally suited for bespoke house designs, and for extensions that need to accommodate dormer windows, multiple valleys, hipped roofs, split-level mansard roofs and the like.

If you want your design to feature big, spacious, open ceilings then the custom build approach is normally best, although some types of trusses can accommodate higher-level ceilings. Another advantage of the old-school approach is that the raw materials are readily available, without the lead-in times required for manufactured components. Building the structure on site is also a very forgiving method that can accommodate last-minute design changes. Plus, traditional timber rafters look great if you want an exposed structure.

The main downside is slower speed of construction and the cost of employing skilled trades to get all the detailing right. Also, the amount of timber required is  greater than for the equivalent trussed roof

8. An all-in-one solution

Panel roofs are very quick to install but are comparatively expensive, not least because they need to be craned into place, with important implications for cost and site access. The big savings come later without the need for follow-up insulation work because it’s already embedded within the panel, making panel roofs ideal for habitable loft rooms. They also avoid the need for inserting cumbersome high-level steel beams. But as with prefabricated trussed rafters, factory-made panels are suited best to fairly simple roof shapes.

9. How is a roof structure supported?

Left to their own devices, rafters have a nasty habit of pushing the upper walls causing them to lean outwards, a common defect in period homes known as ‘roof spread’. This is more of a risk where the lower rafters lack sufficient restraint, a role that’s normally performed by bedroom ceiling joists or horizontal timber ‘collars’ that link opposing pairs of rafters together near their base (structural engineers refer to this as ‘triangulation’).

Rafters are also potentially prone to sagging in the middle if unsupported, hence the need on traditional roofs for large purlin timbers along the undersides, which in turn are propped up by struts or hangers resting on a load-bearing internal wall. Alternatively, steel beams are today often specified to transfer loadings while leaving roof spaces clear. Or, as touched upon earlier, modern trussed rafter roofs can span across the entire living space so only require support from the main external walls.

10. What does a roof structure consist of ? 

Like external walls, roof structures comprise a series of layers designed to provide structural strength and weather resistance. Once the roof ’s skeleton is in place, large sheets of breather membrane are draped over the rafters before being secured in place by horizontal rows of battens nailed to the rafters. Roof tiles are later hung from the battens. The membrane underlay has a dual purpose — to provide a secondary barrier against the ingress of rain, and to allow potentially damaging indoor humid air to escape.

In homes where attic spaces are used for habitation the roof slopes play an extra defensive role as part of the building’s ‘thermal envelope’. They need to be fully insulated to minimise heat loss, in line with Building Regs. High levels of thermal efficiency are easier to achieve where insulation is added at rafter level (‘warm roofs’) compared to conventional lofts where insulation is laid at ceiling level (‘cold roofs’).

11. How to join to the wall plate

To prevent new roofs taking flight at the first gust of wind, it’s obviously essential to firmly join them to the sub-structure below. The primary connection is at the point where the roof sits on the main walls. So a long strip of timber ‘wall plate’ is cut by carpenters ready for brickies to bed in mortar on top of the main wall inner leaf. Wall plates must then be secured with long metal anchor straps that extend down the inner face of the walls below, firmly screwed in place. A small V-shaped ‘birdsmouth’ cut is made in the lower inner faces of the rafters so it neatly interlocks into the wall plate before being secured by nailing. With prefabricated trussed rafters special truss clips are used to secure them to the wall plates. In most cases the ceiling joists ends will also rest on the timber wall plates.

12. What is wind loading, and why does it matter?

Unless roof structures are firmly anchored in place they can be vulnerable to ‘wind uplift’, where extreme wind pressure can cause roofs to literally lift off. This is why building control pay a lot of attention to the various ties and anchor straps needed to secure roofs to the main walls.

So one of the most important aspects of any roof design is to ensure that it can cope with predicted wind speeds in the immediate location of the property. For example, roofs on buildings in coastal regions or on the crests of hills will obviously need to be designed to resist higher wind speeds. Generally, the lower the roof pitch, the more wind uplift will be acting on it. In more exposed locations all roof tiles must be nailed in place and ridge tiles must be mechanically fixed. A structural engineer will calculate wind loadings as part of the design process.

13. Interstitial condensation

Because keeping the rain out is the most fundamental task for any roof, the fact that dampness also emanates from inside buildings can sometimes get overlooked. Unless roofs are properly designed, humid indoor air from daily activities like cooking and bathing can result in serious risks to roof timbers if water vapour finds its way inside insulated roof structures. So to protect the roof structure and prevent any risk of ‘interstitial condensation’ from moisture penetration, vapour barrier membranes need to be incorporated within the inner layer of insulation. Care must be taken not to punch holes in these defences when later installing downlighters and cables. A secondary line of defence against damp can be provided by leaving a clear ventilation path under the tiles so that any trapped moisture is free to safely evaporate. 

14. Rising cost of roof structures

The predominant raw material in roof structures is of course timber. And as everyone knows, timber has been one of the worst affected materials from inflation, roughly doubling in price since 2019. Current forecasts suggest prices are likely to keep increasing because most timber is imported and hence vulnerable to currency fluctuations and global trade restrictions, as well being affected by rises in transportation costs. Roofs also consume large quantities of insulation materials which are mostly petrochemical based and hence vulnerable to world energy price fluctuations.\

INTRODUCTION MODERN TIMBER-FRAME CONSTRUCTION

Modern timber-frame construction in the UK has been developed from North American and Scandinavian methods and bears little resemblance to the traditional, heavy oak-framed buildings of the late Middle Ages. Indeed, most modern timber-frame houses, when built, are visually indistinguishable from their brick and block counterparts. Modern timber-frame construction is based on off-site prefabrication and typically has the roof, the internal and external walls, the first floor and, often, the ground floor built in a factory and then transported to site for assembly.

Although it is not difficult to find examples of ‘modern’ timber framing from the first part of the twentieth century, it did not become a popular form of construction until the 1960s. By the beginning of the 1980s, some 20 per cent of new houses were timber framed, but adverse publicity about quality and construction methods reduced this percentage considerably during the middle of the decade. Since the 1990s, improved design and more rigorous quality control have helped to reinstate the image, and the popularity, of timber-frame housing. The trend by successive governments to encourage the construction industry to adopt prefabrication techniques, such as modern methods of construction (MMC) – see Chapter 1 – as a means of improving quality and avoiding the problems of skills shortages has also given a boost to timber- frame construction. For the past few years, the share of timber-frame construction in the UK housing market has been about 25 per cent.

Timber-frame construction offers several potential advantages for developers over traditional brick and block forms of building. These include:

• faster construction (producing a quick return on borrowed capital and less financial risk) – on-site construction is reduced because of the prefabrication that takes place in the factory. There is also a time advantage because a relatively weathertight building can be formed in a few days and this allows internal work to start quickly. In addition, there is no time lost waiting for the mortar to dry out (as would be the case with masonry) and freezing conditions will not affect site erection (unless an external masonry skin is added)
• less dependence on traditional ‘wet’ skills, such as bricklaying and plastering
• less costly due to the greater use of unskilled site labour
• reduced dead-load resulting in lighter and cheaper foundations.

In addition, timber-frame construction can be relatively easily adapted to encompass high levels of thermal insulation.

Timber-frame construction offers the potential for greater quality control, in so far as this is potentially easier to achieve in factory conditions rather than on site. However, even where stringent factory quality control checks are in place, there may be installation deficiencies in relation to important details, such as vapour control layers, fire stops and cavity barriers, etc. and, therefore, good site management and control is essential. Prefabrication off-site also requires accurate setting out on site – if components do not fit properly, quality may be compromised.

Elements That Contribute Towards a More Energy Efficient Home

It has been estimated that buildings are responsible for 40% of global carbon emissions. Given the ongoing climate crisis, the need to address this has never been greater. One way of doing so is by making your property energy efficient – in the UK, 14% of emissions come from energy use in our homes, and in 2017, consumption actually increased. There are several ways to go about building an energy efficient home and the payoff is not only environmental but will save a lot of money on bills.

Energy efficiency is not just about using sustainable materials and building techniques but constructing your home in a way that cuts energy consumption in half over your over the property’s lifetime. Investment in good design, choosing the best fabric solutions, and installing an appropriately sized heating system are all crucial steps.

Thermal bridging

Central to energy efficiency, a thermal bridge occurs where the insulation of an element is compromised. This happens at junctions, where walls meet floors or roofs, or around openings, doors and windows - and it’s not uncommon for a new build home to contain hundreds of defects.
A solution is to build parts of the home in a factory. With a diminishing number of skilled trades in the UK, modern methods of construction use off site solutions to control quality, improve tolerances and eliminate the energy performance gap. This type of innovation is often considered a risk, but sourcing and relying on traditional trades to deliver an energy efficient home is a risky option as well.

Airtightness

Airtightness is about eliminating unwanted ventilation in buildings, typically draughts around openings and junctions, and it is crucial to get it right at the outset. Houses are made up of lots of incompatible materials so there is a need to interface blocks, timber, insulation and concrete, as well as doors and windows, and that takes a high degree of skill, as these may expand and contract at different rates once the house is heated up.

Insulation

Insulation is critical to achieving Building Regulations, but also will determine the long-term running costs of the house. We advise looking for an optimal thickness level and ensuring that you have high quality installation, as any gaps will seriously affect performance.

Lightweight properties can be prone to overheating, in which case you should introduce thermal mass through a solid floor or solid internal walls to help manage temperature extremes. The thermal mass acts as a passive store, so on hot summer days the building keeps cooler, and in the winter the thermal mass keeps a minimum temperature that can then be topped up by a few degrees to achieve the comfort level required.

Solar thermal and PV panels

Once you’ve built an excellently insulated and airtight building, heat loss can be so small that a traditional heating system would be oversized. Once this need for heating is minimised, hot water becomes the primary demand, so using a cheap and established technology such as Solar Thermal panels can provide hot water across many months of the year, significantly reducing costs. PV panels are not currently subsided through a feed-in-tariff, but integrated PV roofs in various finishes are available to reduce the overall running costs and carbon emissions of the home.

People are increasingly having a say in how their property is built and it’s crucial that they appreciate lifecycle, while having an open mind about offsite construction. To help builders and customers identify what good looks like, BRE has developed the Home Quality Mark, which covers all aspect of a home, environmental social and financial. To provide confidence in buying an off-site fabricated home, BRE has also developed a product standard BPS 7014 to provide confidence in the off-site systems and products being introduced.

Control of Ground Water

This can take one of two forms which are usually referred to as temporary and permanent exclusion.

Permanent Exclusion: this can be defined as the insertion of an impermeable barrier to stop the flow of water within the ground.

Temporary Exclusion: this can be defined as the lowering of the water table and within the economic depth range of 1500 can be achieved by subsoil drainage methods, for deeper treatment a pump or pumps are usually involved
.
Simple Sump Pumping: suitable for trench work and/or where small volumes of water are involved.

Problems of Water in the Subsoil

1. A high water table could cause flooding during wet periods.

2. Subsoil water can cause problems during excavation works by its natural tendency to flow into the voids created by the excavation activities.

3. It can cause an unacceptable humidity level around finished buildings and structures.