Insulation Basics – Brick Veneer Walls

This post will help you understand how much heat you lose through walls. A previous post has explained ‘R’ and ‘U’ values

When considering insulation a typical brick veneer wall would be:

Element

R value

Outside surface air layer

0.03

110mm brick

0.08

25mm cavity

0.12

R1.5 Insulation

1.5

Plasterboard 10mm

0.06

Inside surface air layer

0.12

Total R value

1.91

U value = 1/R

0.51

The heat losses or gains for 150 sq m (fairly typical external wall area) of this type of brick veneer wall at 15 degrees above, or below, outside temperature will be:

Area x ‘U’ x temperature difference = watts per hour

150m2 x 0.51 x15degrees = 1178watts per hour

Heating/Cooling Requirement = 1.17kw/hour

To change the U value calculation simply change the value of the element or add an element in.

Example 1 Changing the Insulation to R 2.0

New Total R = 2.41

New U = 0.41

Reduced Heating/Cooling requirement to 0.92kw/hr

Example 2 Adding a reflective building wrap to example 1 (increases cavity R by 0.18

New Total R = 2.59

New U = 0.39

Reduced Heating/Cooling Requirement to 0.87kw/hr

Remember this isn’t the total heating requirement as heat is also lost through windows, ceilings floors and ventilation.

 

See Insulation for similar Posts

For Posts about Green Building see Sustainability

Artificial Grass v Real Grass

This post was originally published as a guest posted on homeiown.com and has been included here for the sake of completeness.

As I walk around residential areas one thing I have started to see more and more is artificial grass. I have even seen builders put artificial grass on the nature strips in front of their show houses. (Can you still call them nature strips with artificial grass?)

Here are my thoughts on how they compare for use in the home:

Real Grass

Artificial Grass

Installation To get a good lawn requires good soil preparation whether you are going to use seed or turf. It will initially require heavy watering. Artificial grass should be laid on a level well compacted gravel bed. Following the laying of the mat a filler of rubber granules is added and brushed in.
Cost Low for seed to high for turf High
First use Can be a few weeks for turf to months for seed Immediately
Water Use 10-20L/m2 per week in summer without rain Zero
Maint’nce Weekly mowing in summer and regular edging Regular weedkill and monthly raking to keep up appearance
Repair Easy and low cost Difficult and expensive, particularly if it becomes uneven.
Suitability for sport Ok for garden putting greens Good for sports such as tennis as it’s resistant to wear
Enviro Effects Helps absorb CO2 Saves water
Look Seasonal and weather changes also watering dependant Always green
Feel Soft and cool on feet Neutral to pleasant smell Soft but Hot in direct sunlight, static can build up, and has rubbery smell*
Effect on the House Will help keep the house cool No effect
Allergies Can affect hay fever sufferers, especially when mowing No effect

* spraying with a weak solution of fabric softener will help with static and smell

As for me….. well my children have grown up and I don’t like mowing lawns so we haven’t got any lawn, just a native garden.

Which do you prefer?

10 Things Needed For An Occupancy Permit

Did you know you can get an Occupancy Permit before your house is finished?….. Useful to know for all those owner builders who want to move in while they finish.

The point of an Occupancy permit is to protect the safety and health of people who occupy and visit the house and to enhance the amenity.

Here’s the list of things that will need to be completed before you will get a Certificate of Occupancy:

  1. Building is watertight. (roof and walls)
  2. Damp prevented. (Damp proof course OK and ground below DPC sloping away from house}
  3. Roof drainage connected to an approved point of discharge.
  4. At least the kitchen sink and one bathroom are connected and working.
  5. All handrails and balustrades installed. If you have a swimming pool the fences should also be in place. (Even if the pool is empty there is a falling hazard)
  6. Waterproofing of wet areas completed.
  7. Smoke detector/alarms installed and fully operational.
  8. Power installation completed to the satisfaction of the Electricity supply authority. (Power company’s seal on meter)
  9. If gas cooking is to be provided, the pipework is connected to the unit and the house ready for connection to the gas supply.
  10. Water supply connected to the building.

An occupancy permit is not evidence that the building complies with the provisions of Building Codes and Regulations 2006.”

See Types of New House Permits to see what permits you need before you Start

Insulation Basics – Ventilation

A significant factor in the comfort of you house is the Ventilation Rate. No one likes cold drafts in winter., and a burst of hot air in summer can be equally unwelcoming.

So how do you calculate heat losses due to Ventilation?

Well it starts by deciding how many air changes per hour (ac/hr) you have. How often is the air in the areas you want to heat, or cool, replaced.

Its hard to measure the actual changes without specialist equipment however here are some typical values:

  • Old weatherboard property – More than 2ac/hr
  • Typical new house – Around 1 ac/hr
  • Well draft sealed house – 0.5ac/hr

To calculate the ventilation heat loss the following formula is used:

Qv = 0.36 x V x N

Qv – Ventilation heat loss in in W/degree C
V – Volume in cubic m of space being heated or cooled
N – Number of air changes per hour

So for a typical house with a floor area of 250m2 with 2.3m ceilings:

Qv = 0.36 x (250 x 2.3) x 1 = 207W/degrees C

To keep this house at 20 degrees with an outside temperature of 10 degrees would need 207 x 10 watts = 2.07kw/hour…… just for ventilation losses

Good draft proofing will reduce the heating required to 1.04kw/hour. (You would be saving $1 every five hours, more on colder nights)

WARNING
If you have got a flue less heater (such as portable gas heaters, kerosene heaters or bio ethanol heaters) you will need some ventilation to keep a safe level of oxygen in the room.

See Insulation for similar Posts

For Posts about Green Building see Sustainability

 

Plumbing – Kitchen and Laundry

Make sure you have thought about all the following plumbing fittings:

Kitchen

There are a wide range of sinks the choice is a lot wider than one basin or two so you need to spend some time looking at various options. Similarly there a wide range of mixers.

Boiled /Chilled Water Service used to be an office fitting but they are becoming more common in homes.

I think they can waste a fair bit of energy and are a scalding safety risk.

Dishwasher are normally installed as cold fill but there are some hot and cold fill machines around or you can just use the hot water.

Refrigerator with a chilled water service are becoming quite common now.

If you want one of these you will need a cold water line to the fridge recess.

Butlers Pantry

In many larger houses a Butlers Pantry is included rather than a simple larder.

This is somewhere where the messy part of food preparation can be done when you are entertaining.

Depending on how much room you have these can be almost second kitchens so they may need a similar range of plumbing fittings

Laundry

Do you really want a laundry trough?…….. why not have a standard sink basin?

If you go for a trough why not think about a smaller size.

We have found these big enough.

Whichever choice you make you will need either a mixer or taps.

Washing machine – although you may only have a cold fill machine its always worth getting a hot water service installed.

People that do a lot of gardening like a toilet with wash basin off the laundry to avoid them going through the house with dirty boots.

Roof Water / Recycled Water

With roof water tanks and recycled water becoming more common in suburban properties you need to think about where you will use this supply, which has to be kept separate from the mains supply.

Will it be toilets only? or are you going to use it for the laundry?

Its simpler if you live on a rural block because it will be all roof water!…………. If so I would seriously think about a water filter, although I wouldn’t bother for a suburban house with mains water.

Other Plumbing Requirements

My son is a concretor and I work for a drainage company so my wife prefers to wash our overalls in an old washing machine on the back veranda and keep the newer washing machine for her clothes and our best.

 

For similar posts see Plumbing

More plumbing information and 24 pages of Check Lists

in the ‘Selection / Pre-Start Guide’

 

How Much Can You Afford

So you want a new house?

Before you start going around display houses the first thing you need to figure out is how much you can afford. Get this wrong as a couple and it can damage your relationship, and you could finish up with a Ghost House.

Don’t let the marketing convince you to be too ambitious. Its better to get a smaller house and no financial stress than a big house and be struggling for the next ten years. After all its nice to be able to have some money left over after the bills have been paid to enjoy yourself.

The Barefoot Investor talks a lot of sense when he talks about the 20 -10 – 30 Rule. That’s have a 20% deposit, be prepared for a 10% interest rate rise, and don’t have mortgage repayment’s of more than 30% of your wages.

When we started off our approach was that we would borrow no more than I could pay off from my wages while leaving enough for living expenses. We also had mainly second hand furniture.

My wife’s wages went on buying new furniture, home improvements, holidays and luxuries. This meant that if she got pregnant or any other problems occurred we could still keep the house without major stress.

This meant that our first house was a small two bedroom house. Very much at the lower end of the housing ladder, but we were on the ladder, and building up equity for that next step. The running costs of the smaller house were also lower which certainly helped us pay off the mortgage faster before our next house.

Even if you already own a house and are looking to trade up the same financial considerations apply to your next house!

How big was your first House?

 

Budget has more posts about finding a house the right size for you

 

Double Glazing or Smaller Windows?

I’ve posted on Double Glazing but that not the only way to save heat loss through windows so I thought I would do a numerical comparison of the various options for glazing treatment of windows.

In a bedroom of our current house the South facing windows were approximately 4m square (We are in Australia so these windows don’t get any sun).The  basis of my calculations is a difference of 15oC between internal and external temperature.

The equation used to calculate heat loss is:

Heat Loss  =  Area  x  Temperature Difference   x   ‘U’

for

‘U’ single glazing = 7*

‘U’ double glazing = 3*

‘U’ brick veneer = 0.51

* ‘U’ value includes effect of frame.

Option 1 Do Nothing

Heat loss through glass  =  4 x 15 x 7  =  420watts  =  0.42kw/hour

Remember this heat loss is for one room only.

Option 2 Reduce window by 40% to 2.4 m

Heat loss through glass  =  2.4 x 15 x 7  =  252watts  =  .25kw/hour

Heat loss through brick   =  1.6 x 15 x .51  =  12 watts  = 0.012kw/hour

Total heat loss  =  0.25kw/hr  +  0.012kw/hr  =   0.262kw/hour

With our builder this was a no cost option that has reduced the heat loss by 38%.

Option 3 Double Glazing

Heat loss through glass = 4 x 15 x 3 = 180watts = 0.18kW/hour

This is a heat loss reduction of 57% but at a significant cost.

Option 4 Reduce Window by 40% and Double Glazing

Heat loss through glass = 2.4 x 15 x 3 = 108watts = 0.108kW/hour

Heat loss through replacement brick wall = 1.6 x 15 x .51 = 12 watts = 0.012kW/hour

Total  =   0.108kW/hour  +  0.012kW/hour  =  0.12kW/hour

This final option has reduced the heat loss by over 70% and will be around 30% cheaper than double glazing the original large windows.

I hope this has given you some food for thought!

See Insulation for similar Posts

For Posts about Green Building see Sustainability

Block Orientation

Sponsored by Coral Homes

When looking at block orientation a key issue is using the sun to warm the house in winter and keeping the sun out of the rooms in the summer.

Typical blocks in Australia are rectangular. About twice as long as the block width, as are most home designs. This limits the way you can place the house. In my experience the order of preference of blocks is.

1. Facing East
2. Facing West
3. Facing South
4. Facing North

If you have got a block at an angle it will require a bit more thought unless you can orientate the house in one of the above preferred directions. Larger blocks and square blocks make adjustments to the house orientation easier.

My reasons for the preferences are as follows:

Facing East

This orientation allows one of the long sides to face north making the best use of the sun in a passive solar house. Usually the master bedroom is at the front so even in the summer the low sun morning sun only warms the bedroom from the chill of the night. Windows can be minimised on the west side to stop the house overheating in the afternoon and evening. This orientation also gives you plenty of roof area for the most effective location of solar hot water and solar electricity panels.

Facing West

Again like the east facing block you can have one of the long sides to face north making the best use of the sun in a passive solar house. With a master bedroom at the front you will need to take steps to keep the afternoon sun out of the room to stop overheating. Like the East facing orientation this is useful for solar panels on the roof.

Facing South

With a house facing south the best layout is to have as many rooms as possible having large windows facing north which can be difficult on a narrow block. To make the best of this orientation you may need to have plans drawn up as most standard plans don’t suit this orientation. It’s also best to minimise west facing windows.

Facing North

A north facing house is probably the least desirable on a suburban block as it makes it hard to get the sun into the house. I certainly wouldn’t want big north facing windows allowing passers by to look in.

 

Lots more information in the anewhouse Guide to Buying a Block for only $4

See similar posts see Choosing a Block and Passive Solar

 

Building Inspection – Compliance not Quality

Guest post by David Swinson, BDC Building Design Compliance Pty Ltd

One of the key misunderstandings by new house buyers is the role of the building surveyor with respect to building quality of their New House.

Many consumers  believe that inspections by building surveyors against the minimum standards of the Regulations are also an inspection of work quality specified in the contract. This belief is incorrect, some of the key objectives of compliance with regulation are:

    • To protect the safety and health of people who use buildings and places of public entertainment; and
    • To facilitate the cost effective construction and maintenance of buildings and plumbing systems.

The House contract between the owner and the builder for a new house construction includes the following aims.

  1. To provide for the maintenance of proper standards in the carrying out of domestic building work in a way that is fair to both builders and building owners; and
  2. To enable building owners to have access to insurance funds if domestic building work under a major domestic building contract is incomplete or defective.

An example of the differences would be:

If a builder ran out of bricks during the project and finished the wall off with another type of bricks.

  • As far as the building surveyor was concerned the wall would be structurally sound and would therefore meet the objectives of the regulations.
  • As far as, you the owner, is concerned a wall of two different types of bricks would definitely not be what you required.

Your remedy however, would be through your building contract, not the regulations.

David is the author of the informative Building Regulations Blog where you will be able to find more articles on Building Regulations Issues

 

For more posts about quality see Gettting It Right

 

Starting House Design 1- Bubble Diagram 1

A big mistake in designing a house is to get involved in detail too quickly.

Rough sketches of a floor plan, which you can easily change, are the best way to start. . . . Much better than using a computer drawing tool which can  ‘Lock You In’ and stop you considering different ideas.

  1. Decide what rooms you need and the approximate size of the house (see How Much House?)
  2. Draw some bubble diagrams. . . . These are drawings where each bubble represents a room, or a feature of the house.
  3. Work quickly, while thinking, and discussing, how you want the various rooms to relate to each other.
  4. As you develop the plans try to draw the bubbles to roughly represent the room sizes, but don’t try to be too accurate.
  5. Because the drawings are done quickly you can easily do new ones as your ideas develop.
  6. Don’t throw the old one out though! You might want to go back to a previous idea.

The collection of diagrams will be a demonstration that you have gone through a process of developing a design rather than infringing someone else’s Copyright.

The above illustration is a tidied up version of the initial bubble diagram for our first Australian house. It was based on certain things we wanted in the floor plan. These were:

  • A rectangular plan to keep things simple and economical
  • A passive solar house with the main rooms facing North
  • A wood burning stove in the centre of the house
  • Our bedroom at the opposite end of the house to the children.

Next  I will show how we developed the initial bubble diagram to a refined version which we could then use to develop the final floor plan.

 

For more Posts about Design see Floor Plans