Matt Cornell is a structural engineer with 25 years experience in residential structural engineering. He lives in Northgate on the northern side of Brisbane, Australia.
This little thing is a hydrostatic valve. It goes in the bottom of your pool to stop the pool from floating (or buckling) if the water level on the outside of the pool is higher than the level on the inside.
It doesn’t have a rated flow rate or a rated differential pressure.
But if it doesn’t work your pool might float out of the ground.
I used to think rainy days would fill a pool as quickly as the ground around a pool hence there wouldn’t be a need to worry.
But if you have bad site drainage and water runs towards your pool there is a very real chance your empty pool could float.
Whether you could claim for damage to your pool from ‘flood water’ depends on your insurer – but we all have access to aerial photos and we can tell if your pool has been empty for a long time.
Bottom line: take the hydrostatic valve out of the bottom of your pool when it is empty. Only put it back in when you intend to fill your pool up.
Efflorescence. What is it? How does it affect your building? Is it bad and what do you need to do about it?
I’m Matt Cornell from Cornell Engineers. Let’s have a chat about efflorescence and what it means for your building.
Efflorescence is that salty substance that appears on walls and slabs and sometimes even ceilings -that is a sign of moisture coming through the surface.
By itself, it isn’t a structural defect but it’s a sign that something’s going on that needs further investigation and that your building needs some help.
So if we have a look at a couple of these photos, you can see that there’s blockwork, and salt coming through on the wall.
The wall itself is discolored in place – it’s a little bit darker around where the salt is located.
That’s part of the sign that you know that there’s moisture coming through.
So efflorescence is actually the salt that is left on the surface after moisture migrates through your cementitious or blockwork or brickwork surface.
The moisture dissolves salts out of the brickwork or blockwork or concrete and when the moisture comes to the surface the moisture evaporates leaving behind the salt crystals.
So it means there’s moisture coming through your surface and that means there’s moisture on the other side of the surface that needs to be handled, addressed and that problem solved.
Now again, efflorescence by itself is not a defect. It’s not a problem. It’s a sign of a problem.
It’s a sign, generally, of a moisture problem and that means you need to find that moisture and solve that problem.
When we look at what that looks like on paper in a wall, if we use a concrete measuring wall for example, and it might even be say a retaining wall where we know that there’s dirt on the other side of the wall when we’re standing on the inside and if there’s efflorescence on that surface then that’s a good sign that moisture is coming through the blockwork wall evaporating on the inside of the surface and leaving those salt crystals.
So you as the owner or the occupier or the person in charge of the maintenance for that building now you know that you need to go onto the other side of the wall find out where that moisture is coming from and solve that issue.
So we’ve already done quite a long video on solving drainage issues on houses on sloping sites and this ties in nicely to that in that moisture problem is going to be solved by doing some of those things in that video.
Once that solution has been attempted then it’s time to do some cleaning – take the efflorescence off the wall.
There are some quite good products that you can buy from hardware shops to dissolve efflorescence and take it off walls and surfaces and then wait to see if the efflorescence reappears – after you’ve solved the moisture issue. So, solve the moisture issue first.
Clean the efflorescence.
See if it comes back. If it comes back you’ve still got some more work to do – still got some moisture issues.
Now the other issues related to moisture coming into a building are the same things that we spoke about in the other video.
That steel reinforcement, for example, corrodes when it comes into contact with moisture.
The other things are leaks, the rot of timber, and mold.
So the moisture that’s coming through and causing leaving efflorescence could also be causing mold. And finally, uneven soil moisture conditions can cause house movement and damage and we cover that on our website.
So efflorescence. Not a problem itself but a sign that your building needs some help.
You might be tempted to engage a structural engineer if you are selling your cracked house to write a report to explain that those cracks are only superficial cracks.
After all, the cracks have been there forever and you never worried about them.
G’day. This is Matt Cornell from Cornell Engineers.
Today I’m answering one of the questions we get quite frequently and that is, “Do we, at Cornell Engineers, do inspections and provide reports for people who are selling their house?”
So, Tom, for example, was selling his house. He noticed cracks in the walls and thought that it might be a good idea to get an engineer’s report before he put his house on the market. His intention was to show the engineer’s report to prospective buyers and allay their fears.
Now while this sounds like a good idea in theory, what we have found is that most buyers do not trust the seller’s engineer’s report.
So, in fact, Tom if he were to engage us so that he could sell his house or to provide a report before he sells his house, is probably just wasting his time and his money.
Why?
Because the first buyer that comes along or the buyer that comes along is more than likely going to read the report, not trust it, think that it’s been provided for the seller for the seller’s benefit, and then go out and get their own report.
The fact is engineers should be writing reports independently of who is paying them but that theory, or that feeling that people are worried that they can’t rely on the engineer’s report, that’s a real concern.
So our solution is, instead of Tom coming to us before he sells the house or as he’s preparing the house for sale, we recommend just about every time, that Tom and the buyer once he has a contract, engage the engineer together.
That way the buyer can attend the engineer’s inspection with the engineer. They can ask any questions that they feel like they would like answered They can have their name on the engineer’s report when it’s issued.
Even though Tom is maybe even paying fifty percent or a hundred percent of the report, it allays the buyer’s fears.
It becomes the buyer’s report or it helps the buyer feel more satisfied that the engineer has done a good job and is acting for both parties and it allows the buyer to ask the questions they want.
Building and Pest Report
Now don’t forget we also recommend that most buyers undertake a building and pest report.
On our website, we’ve talked about this.
Those building and pest reports, even for me, are a valuable resource and when I purchase properties, most times, we tend to get a building and pest inspection report as well.
So it’s that good. We definitely recommend using a building and pest inspector.
We have attended site inspections with the building and pest inspector – but more often than not it’s better value for money if the engineer attends to inspect a building after the building and pest inspector has been to answer any questions that remain.
Building and pest inspectors are required or tend to in any case, have a lot of recommendations to seek specialist advice, and a lot of that time, that tends to be structural engineering advice.
So we’d normally recommend that a building and pest inspection is done first and then if there are any structural issues that are raised in that report then you go out and you get your structural engineering report at that time.
This has been Matt Cornell from Cornell Engineers. I hope this has clarified our feeling or the best way we think you could spend your money on an engineer’s report if you are selling your cracked house.
If you’re buying or selling a house, we’re based in Brisbane. We’re working all across the state and at the moment, in fact, I’m coming back from Stradbroke Island, so we get around.
Give us a call if we can help you and we’ll see what we can do for you.
I was asked the other day what’s my number one piece of advice for someone who is having a house being built right now and my answer would be to take lots of photos all the way through construction even if you don’t know what you’re taking photos of.
Now, why is that?
If something goes wrong with the house later on, a set of photos during construction allows the engineer to see through walls and see through concrete slabs.
It allows us to see how a house went together so that we can help diagnose what went wrong.
Does that mean we don’t think you need to get an independent inspector during construction?
No, it does not.
It means an inspector is still a great idea but you should do everything you can to take as many photos as you possibly can during construction of as many elements as you possibly can.
