Factors that affect indoor air quality

Indoor air quality has always been a concern in healthcare settings and controlled industrial environments (e.g. ‘clean rooms’) but the COVID-19 pandemic has raised awareness of the threat of indoor air contaminants.

That can include viruses and bacteria, but also other irritants like dust and pet hair, and potentially harmful gases like carbon monoxide, carbon dioxide, nitrogen oxides and ozone.

But what are the main factors that affect indoor air quality? There are three main groups of risks – and not all of them derive from inside the building.

In this article we’ll take a look at the three major factors that affect indoor air quality, and break them down into some specific sources of contaminants.



Indoor activities can have a direct impact on the quality of the air in the room, and this is especially true in sealed environments, such as interior rooms with no windows or artificial ventilation.

Some examples of indoor sources of air contamination include:

  • Human activity (personal hygiene, smoking)
  • Maintenance work (new carpet/furniture, pest control and redecoration)
  • Cleaning (surface sprays, agitated dust, artificial odours)
  • Equipment (e.g. toner particles from printers and photocopiers)
  • Leaks and spills of liquids
  • Number of people in the room (especially if very high)
  • Temperature/humidity – see HVAC Systems below

Behavioural change and best practice can mitigate some risks, but in any indoor environment you should monitor air quality for any dangerous deviations, even where HVAC systems are used to improve ventilation.



It’s quite possible for activities outside the premises to have an impact on indoor air quality, especially around main entrances and open windows. This is one reason why designated smoking areas are not immediately adjacent to entrances and exits.

Other risks in this category include:

  • Airborne contaminations (pollen, vehicle exhaust particles, other air pollutants)
  • Nearby emissions (delivery/loading bays, waste disposal activities)
  • Building exhaust emissions that re-enter the premises
  • Mould and mildew from stagnant water (Legionella risk)
  • Soil gas (e.g. from pesticides or underground storage tanks)

Always monitor air quality around entries and any large windows that are routinely opened, to highlight risks arising due to nearby outdoor activity, especially persistent activity that creates an ongoing threat.


HVAC Systems

Finally, HVAC systems are intended to improve the comfort and safety of occupants, but when poorly maintained they can lead to a variety of indoor air pollution risks:

  • Poor distribution of fresh air around building
  • Transported dust from inside ventilation ducts
  • Poorly maintained filters in need of cleaning or replacing
  • Biological risks from poorly cleaned ducts and humidifiers

Again this last risk raises the chance of a Legionella outbreak, in the presence of stagnant water and moist dirty surfaces, and HVAC systems should not be overlooked in the pursuit of clean, dry indoor air.


Find out more about how you can improve the indoor air quality of your property with a HVAC system by giving The hebs team a call on 0151 2360707.

Maintain your drains for Spring

As we move towards the Spring months, it’s one of the most important times of the year to maintain your drains.

The Winter brings some of the worst weather conditions overall, but Spring can bring a sudden spike in rainfall, as the warmer air can hold more moisture.

Because of this, February is usually quite dry in colder years, while March often stands out as unusually wet compared to the surrounding months.

This is compounded by delays to building maintenance in the inclement Winter months – so if you’ve been thinking “I’ll wait until the weather improves” now is the time to get any blocked or slow-flowing drains cleared out.


What are the risks for blocked drains in Spring?

Springtime poses several different risks for blocked drains, including the heavier rainfall totals mentioned above, and delayed maintenance to unblock drains in Winter.

Some other threats to look out for include:

  • Any remaining blockages due to fallen leaves in the previous Autumn
  • Sludgy deposits left behind by Winter grit/salt or thawing snow/slush
  • Larger detritus dropped into drains and gutters on windy Winter days

You may simply not have noticed your drains are clogged, due to staying indoors in bad weather, or poor visibility on dark and foggy days.

With more hours of daylight to use in the Spring months, take the opportunity to give your drains a good inspection – or call out the hebs Flowtech team on 0151 2360707 to take care of it for you.


What if my drains are blocked?

A blocked drain can be a big problem in terms of flooding and damp masonry, but it’s a relatively easy issue to fix.

The hebs Flowtech team use cutting-edge technology to reach the drain or gutter, whether it’s at roof level or below ground, and remove any solid debris that’s blocking it.

Usually there will be some sludge clogging the pipe or gutter too, and we use high-powered jets to blast this away without damaging the drain itself.

We pride ourselves on a job well done, which is why in our case studies you’ll see all kinds of gleaming grates, grids and gutters, drains and downpipes, which we always aim to leave looking as good as new.


Don’t delay drain maintenance

Nobody knows when the next downpour is coming, so if you think you have a drainage problem, don’t delay in calling us out to take a look.

It’s likely to take just a few hours of drain maintenance to get things flowing freely again – compared with a potentially costly repair to masonry due to damp problems caused by overflowing rainwater.

How work from home will shape the future of residential and commercial construction

One trend that has emerged from the Coronavirus pandemic is an immediate and substantial increase in the number of people who work from home.

During the first national lockdown in the UK, employees were asked to work from home wherever possible, to reduce social interaction in the workplace and therefore reduce the spread of COVID-19.

The UK has had a legal provision in place for many years that allows employees to request flexible working conditions, but the past 12 months has served as a ‘proof of concept’ for large-scale homeworking nationwide.


Who works from home?

ONS figures published in July 2020 showed that in April, when the first national lockdown had just been imposed, nearly half (46.6%) of UK employees did at least some of their work at home.

Of those, 86% did so directly because of COVID-19. In London the proportion of people working from home was higher at 57.2% and a staggering 91.6% cited Coronavirus as the reason why.

While many people will be able to return to the workplace as the pandemic eases – perhaps over the course of 2021, thanks to the vaccination roll-out – the past 12 months may have highlighted previously unconsidered benefits of homeworking for employees and employers alike.


What does this mean for residential construction?

The most direct implications of all this are for the future of residential construction post-COVID-19.

For those forced to work from home over the past year, the challenge has been to find a suitable workspace, free from distractions, while still achieving a clear divide between work and ‘home’.

Residential developers will need to factor this into more future builds, whether this means creating additional space for a work area in the kitchen, reception room or master bedroom, adding an extra room for use as a study, or even construction a garden building.

Mains electricity and high-speed internet are a must in any such area, and a landline telephone socket may also be beneficial, so buyers and tenants have no reason to reject their potential future workplace.


What about commercial construction?

There are fewer obvious implications for commercial construction, but if a significant proportion of clerical workers move to be home-based, this could lead to a drop in demand, making it more important to create attractive and well-appointed workplaces.

More people working from home for only some of the time might increase the need for flexible workspaces and hotdesking, rather than workstations reserved for a specific person.

As such, commercial developers might find even greater demand for open-plan offices, which can easily adapt to the precise mix of individuals who are working in the office on any given day.

See what The hebs Group can do for you with our professional and reliable construction services readily available for any type of residential or commercial project.  Call us today on 0151 2360707 to get in touch.


The importance of Construction Material Testing

Construction Material Testing, or CMT, is the process by which materials are tested before they are used in new building work, refurbishments and extensions.

The precise definition of CMT depends on the job and on the materials used. For example, you might need to test the tensile strength of a load-bearing building material, or the porosity of a material that will be used in a very humid environment.

However, the intended outcome is always the same: to ensure that materials are safe and reliable, and that they will do the job for many years without expensive maintenance, without damage to the building, and without endangering property or human life.


Types of Construction Material Testing

There are two main types of Construction Material Testing:


Laboratory Testing

A lot of CMT happens in the laboratory, before materials are shipped or even specified. This allows precise characteristics to be listed on product datasheets, so that you can choose the correct materials for the job without needing to test them yourself.

Alternatively, you might request a sample or buy a small quantity of a particular product, carry out laboratory testing yourself, and only then specify it for use at scale across your project.

In some cases, laboratory testing is used as a follow-up if field testing of construction materials proves inconclusive, or if the results obtained are on the border of acceptability.


Common Types of Laboratory Testing

There are many types of laboratory testing but some of the most common construction materials tested in the laboratory include:

  • Asphalt
    • Bulk specific gravity
    • Density
    • Flow
    • Gradation
    • Stability
  • Concrete/Masonry
    • Absorption
    • Compression strength testing
    • Efflorescence testing
    • Flex strength testing
    • Structural masonry testing
    • Tensile strength testing
    • Unit weight
  • Soil
    • Bearing ratios
    • Chloride testing
    • Classification
    • Compressive strength testing
    • Hydraulic conductivity
    • Permeability testing
    • pH testing
    • Swell testing

This is not an exhaustive list, but it shows some of the physical properties that can be verified in the laboratory, before a particular product is used on a job.


Field Testing

Field testing is an important on-site process, especially in industrial developments such as utilities, transport infrastructure, airports and so on.

Like lab testing of construction materials, field testing depends on the specific materials already on-site or intended for use in new development, and can include asphalt, concrete, masonry, timber, soil, steel and more.

Common characteristics checked using field testing include strength, compaction, moisture and air content, and wherever possible these are verified via a combination of visual inspection and non-destructive methods to avoid damage to the materials in situ.


Why is CMT important?

Testing construction materials gives developers confidence that they are fit for the job. Testing by manufacturers also allows the correct products to be specified upfront.

On-site testing ticks the necessary health and safety boxes and allows developers to offer guarantees over many years, without facing costly remedial work in the future.

For all of these reasons and more, you should always be aware of your obligations, but you should also see CMT as a way to protect your investments and your workforce alike.


For more information about our construction services, give us a call on 0151 2360707 and we’ll be happy to help with your enquiry.