building on unstable ground

Working With Reactive Soils

When it comes to extending or building a new structure on the ground floor the type of soil in which we will be working with is important to identify. Various suburbs of Adelaide are known to have reactive soils locations such as Oakden, Lights View, Northgate and Aberfoyle Park. Our recent project was undertaken in Aberfoyle Park as you will see below.

Ground Movement When Building

A client recently contacted us to investigate some ground movement along the side of there house. The area in question wasbuilding on unstable ground located outside two of there bathrooms and it was covered by an over head shade sail. The first thing to do was lift the pavers and see what condition the soil is in below. Immediately upon removing a few pavers it was noted that the soil was all very wet, spongey and there were air pockets present. The next step was to keep excavating until dry soil could be found, unfortunately this did not happen, and the soil continued to get more saturated the deeper we went to nearly 1 metre in depth. It was at the depth of 1 metre the soil had become black and almost 100 percent saturated, it was like digging in a swamp!

Why so much moisture this deep in the ground?

As previously mentioned, Aberfoyle Park is known for having reactive soils meaning that they are likely to shrink and expand due to the nature of its makeup. When we encounter such conditions its crucial that various precautions are put in place to protect items such as the concrete slab, external fixtures and services running under and into the building. The concrete slab is likely to have more steel installed in it and have thicker areas to help it maintain its integrity when the soils shrink and expand. Services such as plumbing drains should have expansion and swivel joints installed to allow the drains to move without causing damage to the pipes.

When the hole was further excavated, we found that the sewer drain was in this location and could well be responsible for what is allowing all this moisture into the hole. We followed the direction of the sewer drain to the underside of the perimeter footing where a small pond was found. Between the water membrane and the concrete slab was a huge amount of water just sitting there. The main sewer pipe which ran from outside the home’s perimeter and through the middle of the house to pick up the kitchen and laundry sinks had snapped in half (as seen in image) this was the cause for so much moisture in this area.

How to fix such a problem?

In order to have this issue properly fixed we needed to now engage one of our plumbers to attend the site and asses the damage. The drain was further excavated to see what condition it was in down stream as the system was still holding a large amount of waste water. The drain was exposed another few meters where it was identified as having collapsed due to ground movement in this area also. The lack of any type of flexible connections or expansion control devices certainly did not help, and the lack of quality fill being used provided a deadly combination which lead to this disaster. We would now need to identify a suitable point in which to join back onto the sewer system and then carefully re-install the drainage system with the correct swivel and expansion connections to prevent any future damage to the pipe system.

Making good of the bad situation

Once the new sewer drain had been installed using the required swivel and expansion fittings and then tested it was time to have all the contaminated spoil removed from the site and new class A material imported to begin the backfilling process. Carefully the trench was backfilled and compacted in layers to ensure good support for the pipes and for the pavers which would be re-installed. Once all backfilling was completed it would be time for our paver to attend and cut the pavers to now allow for the new inspection openings for the drain to be raised to surface and install the pavers.

Working with reactive soils is always a challenge and can cost more in the initial build stages BUT as you have just seen in this situation for the sake of a few hundred dollars’ worth of flexible connections and some good quality imported fill a situation such as this may have been avoided. When it comes to building there should never be any short cuts taken because the consequences can be disastrous.

fire code in constructing buildings

Protect Your Property From Fire Damage

The NCC and Australian Standards have strict rules and methods of which must be adhered to when building or renovating a property, whether it be commercial, industrial or residential.  These processes have been put in place to protect human lives and restrict damage to buildings during the event of a fire occurring.

When we look at class 1 through to class 10a buildings we must ensure these buildings are either built at correct distances from one another, separated using the correct fire rating methods, provide adequate access during a fire or a combination of all rules.

fire code in constructing buildingsWhat are some examples of correct building practices to ensure fire safety?

  • 900mm is the distance in which any class 1 building must be built as a minimum from a boundary that it is built on. If, however there is another building on the same allotment the distance is increased to 180mm between the two buildings.
  • Class 1a buildings such as town houses, terrace houses and dwellings attached by a common wall must be have the wall which joins the two properties constructed of a fire rated material. Typical construction methods used to create this barrier are double bricked walls protecting each property from one another during a fire starting.
  • Commercial buildings such as Class 5 and Class 6 may have penetrations going through the floor or dividing tenancy walls for systems such as air-conditioning, electrical and plumbing services. These must be sealed using approved products such as fire collars, fire rated mastic and fire rated pillows.  All of these are designed to stop the spread of fire through the penetration as they close over the opening when in contact with fire.
  • Cladding of structural members to ensure their integrity during a fire. If we look at multi storey construction the steel members which are used to hold up and tie in the building need protection from a fire for a certain period to enable the fire to be bought under control.  In a situation where the steel column or beam may form part of an internal feature it will be cladded in fire rated gyprock so that it can still be painted and or decorated.  If, however the structural member is concealed in a ceiling space or a plant room you might see it encased in vermiculite.

Building in a bush fire zone

Adelaide has many locations where Class 1 to 10a buildings are built and susceptible to bush fires.  Take for example the Adelaide Hills this is classed as a zone that would be more likely to endure the affects of a bush fire as opposed to somewhere such as Unley.  When it comes time to get approval for a building or structure to be built it must be approved against what Bushfire Attack Level it faces (BAL).  There are 6 levels of bushfire protection legislated and these are:

  • BALzone low = General bushfire area
  • BALzone 12.5 = Medium bushfire area
  • BALzone 19 = High bushfire area
  • BALzone 29 = protection level more than high
  • BALzone 40 = protection level more than high
  • BALzone FZ = protection level more than high (most extreme level in the NCC)

Depending on the risk to fire your building is going to be zoned it will depend on what specific requirements the site will need to meet.  Below are some examples of the requirements relating to each zone:

High risk protection planning provisions:

  • Have a dedicated water supply of a minimum amount of 22,000 litres
  • Ensure any gaps between dwelling floor and ground are enclosed to prevent burning debris from entering
  • Be constructed at a minimum of 20 metres from flammable and combustible materials
  • Located and designed to minimise the risk from bush fires
  • Provide adequate access to and from the property for vehicles including fire fighting machinery during the event of a fire

Medium and general risk protection planning provisions:

  • Have a dedicated water supply of a minimum amount of 5,000 litres
  • Ensure any gaps between dwelling floor and ground are enclosed to prevent burning debris from entering
  • Be constructed at a minimum of 20 metres from flammable and combustible materials
  • Located and designed to minimise the risk from bush fires
  • Provide adequate access to and from the property for vehicles including fire fighting machinery during the event of a fire

Protection from fire is one of the most vital components of any building project and adhering to the NCC and Australian Standards is something that cannot be cheated on.  These rules and legislation have been put in place to protect human life and structures.  When considering building in a bush fire zone you should always obtain the services of a qualified builder who can ensure that your project will adhere to the correct fire safety rules, your life might depend upon it one day.

 

 

 

Selecting The Right Screw For The Right Job

If you are attending your local hardware store there is what would seem to be endless choices for the right screw for any project, and there’s a good reason.  Screws can be subjected to varying weather conditions and this will have an impact on the type of screw you should be selecting.

What screw for which purpose?

When we are dealing with a simple task of hanging a picture frame majority of people just use whatever is available and even perhaps just a basic small cheap nail which is fine.  But when we are considering a screw which is going to be responsible for holding a load and may not be physically accessed again once installed there are a few points worth considering:

  • What weight will be placed upon the fixing (load bearing or not?)
  • Is the screw directly exposed to the environment or concealed?
  • What type of conditions will the screws be exposed to?
  • Will the screws be coated or left raw?

Once we have established a few of these points its onto considering the types of materials screws are made from and what will suit your project.

old screw stuck in a wallWhat materials are screws made from?

Majority of the screws on the market today are made from some form of metal, it is the type of metal that a screw is manufactured from which will influence the application it should be used for.  There is also the thickness of the screw which will determine the strength of the screw typically referred to as the gage of the screw.  So, let’s explore a few of the common materials and uses for screws:

  • Stainless Steel: Screws made from this material are going to the most expensive fixing you will purchase, and, in some cases, you may need to take a breath before shopping for these screws.  Areas where exposure to high levels of corrosion is where these fixings should be installed.  For example, buildings near coastal areas and projects where moisture levels are high will benefit from the corrosion resistant characteristics of this metal.
  • Galvanized Coated: A coating applied to fixings (hot dipped galv) to assist in the prolonged life of the screw.  This fixing is a dull grey in its appearance and are typically used in situations where the screw will no longer be accessed again once installed.  For example, the installation of equipment inside of a wall or ceiling the void, you want the fixing to remain strong its entire life but cannot get to get again without ease.
  • Zinc Plated: Probably the most common form of screw used in the building and renovation market today.  These screws a gold/yellow colour in appearance, they are not so much of a heavy-duty screw but more a light weight fixing.  For example, dry wall installers use these to assist in the installation of dry wall to either a steel or timber frame until the adhesive has gone off.  You will also occasionally come across the screws being used in situations where they are not suitable.  The image on this page shows where a home handy man has used zinc plated screws to secure a soap dish to the wall and due to this high exposure to moisture the fixings have rapidly deteriorated.
  • Aluminium: Light weight yet extremely strong with high corrosion resistance and good performance in extreme temperatures.  As equally expensive as stainless steel and only used where they are specifically required.  For example, air crafts and motor vehicle which require a fixing that has a minimal impact on weight and can relied upon for its strength.
  • Brass: A softer metal with a bright yellow colour.  These screws are found quite a bit in the plumbing industry where the screw will be installed in a location where it will directly be touching copper and occasionally exposed to moisture, this material is both compatible with copper (won’t react in a negative way with it) and will also provide a good level of corrosion resistance.  Certainly, one of the least used screws today in the building industry.

Slotted, Posi or Star?

Once you’ve decided the type of screw you will also need to establish how it will be installed.  The three most common styles of heads you will find on a screw today are a flat (slotted) screw, posi drive which has a square inserted in the middle of the head and star shape also known as Phillips which has five points and looks like a star.  Posi drive screws are used mostly where the screw is not to tampered with as you need a special shaped driver to insert and remove again.  Today the most common head is the Phillips head and over 80% of the screws you will find in a hardware store or installed will have this style of head.

insulating your home

How Important Is Thermal Insulation?

It is something that can be over looked either during the design phase or construction process and even after many years of building being in operation the thermal protection may need maintenance. Today many designers and engineers are across the many available options on the market but like everything it comes down to price, BUT with the wrong product or no thermal protection the longer-term costs will almost be guaranteed to out way the initial costs back in the building process.

What areas of a building does thermal insulation impact?

Thermal insulation comes in many different forms and provides the same service to each area it is applied to. The design is to assist with lower energy bills through maintaining steady/constant temperatures to the material it is associated with. An example is the older properties we renovate in Adelaide such as Unley and Myrtle Bank have no insulation on the underside of the sheet iron allowing for a variety issues such as noise and excessive amounts of temperature differentials in the roof space to occur.

insulating your home

Case Study

We recently under took an energy audit of a block of 50 apartments in the suburb of Plympton in South Australia. There were various suggestions put forward to assist with energy conservation such as sensor activated lighting, roof ventilation to help hot air be expelled during summer, decrease draft entering under doorways, double glazing of glass, water saving shower heads, thicker curtains and solar electric panels on the roof for electricity. One of the main issues which has been immediately dealt with was the thermal protection to a large commercial scale water heating plant.

Approximately 10 years ago a contractor was engaged to upgrade some of the infrastructure which provides huge amounts of hot water to the large volume of showers and baths at this facility. The installation was very poor and as you will see in the photos below majority of the pipe work which carries hot water into and around this apartment complex was missing or barely had any thermal protection. What this meant is that you have copper tube carrying 65 degrees of water exposed to elements allowing for a huge temperature drop. In turn the water heaters were working a lot harder then needed and the client’s energy bills were through the roof.

A process such as the one described above was labour intensive, but even by the time we had completed only a third of the new pipe work insulation the increased temperature being kept inside of the pipes could be felt as we installed the insulation, the pipes were becoming warmer and even to a point towards the end of the process where they were hard to handle because the temperature of the water was being maintained to higher level. This entire process took a total of two full days and two staff members.

insulation for home heating and cooling

Keeping the costs low

With the continual rising of energy bills it has become increasingly harder for businesses to maintain the running costs while still trying to remain competitive in the market place. It is crucial that every part of the business is operating in an energy efficient manner. Sometimes businesses need to spend a bit of money to create a better environment in which they can start to save money. Today there are still state government incentives and rebates on offer for certain energy saving methods which not only gives the owner a money credit but the appliance being installed will immediately start to impact on the lowering of utility bills. If you are considering trying to decrease your utility bills contact us today and let us perform an energy audit on your property.