Since my blog post detailing the drainage issues Henley left me with, I’d planned to add an Agi pipe along the front of my home to assist in evacuating the water that was ponding near the slab. In preparation for those works I came across a construction drawing which Henley was supposed to have followed.
The drawing specified that there was meant to be 4 silt pits, 2 spaced across the front of the house, 2 spaced on the south side of the house, all connected via 18m of underground Agi pipe. I could only find 3 pits. Maybe Henley forgot the 4th one, I wondered to myself.
Trying to get to the bottom of the mystery, I went back through my photos taken during construction and discovered the photo you can see below. This pic was taken before the slab was poured in July 2022 and the pit you see furthest the camera was the pit that was now missing.
Upon re-reading my building contract and the drawing (at the top of the page) that forms part of it, it became clear that Henley were in fact responsible for providing adequate site drainage. It had to comply with both their own engineering consultant’s specifications and the relevant Australian Standard, AS2870 (page 46). It did neither.
When I sent Henley a warranty claim they eventually sent a plumber around, unannounced, to find the missing drain. After an hour or so he managed to find the drain roughly where I thought it should be.
Unfortunately for him, and Henley, the pit was around a half meter below the natural ground level. The plumber had to battle his way through a thick layer of clay and a hard, blue, toxic layer of builder’s sludge which stunk of turpentine and paint.
To make matters worse, the sludge and clay had completely blocked the Agi pipes that connected the pits across the front of my home. They remain blocked as at the date of publication.
Looking more closely at the construction drawing I noted that Agi pipe must be laid at least 1500mm from the slab if it is to comply with Henley consulting engineers specs. If you look at the photo above you will see the 2 pits connected by the orange line where it’s assumed the Agi pipe has been laid. The yellow tape measure in the same pic shows you where 1500mm would be. In other words, Henley laid the Agi pipe far too close to the slab. This will not comply with AS2870 or their own construction drawings. More importantly, it puts the long-term integrity of my concrete slab and warranty at risk.
Furthermore, even a rudimentary understanding of how Agi pipe works would tell you that you never lay clay over the top of the pipe as this restricts the flow of water into the drain. Check out minute 4:40 on the below video for a basic rundown.
Just today I notified Henley that I wish to claim a warranty for the defective drainage around the perimeter of my house, as specified in item 5 in this independent inspection report I gave Henley in October 2022. No, the item has still not been rectified, despite appearing in all my inspection reports, nor does it comply with AS 2870.
There are so many little problems with my home that could have been worked out cheaply and quickly if Henley chose to work constructively with me during construction. Instead, they attempted to block my access to site so they could cover up their mistakes.
In closing, I’d like to point out that Henley’s site supervisor signed off on all of this, Henley’s construction manager signed off on it too, but worst of all, the supposedly independent building surveyor, the ones that signed my occupancy permit, also failed to detect any of this.
Henley really is incompetent.
Thanks for all the posts. Really helpful! I am also worried about drainage. Although looking at the plan you provided, the pipes are pvc pipes and not agi pipes? Reading the legend, the drains is recommended to be 1 m from the edge of the footing but can be as close as 60 cm without site specific engineering advice?
Thanks for the comment. Your post has alerted me to the fact that I have posted the incorrect drawing which I will remedy when I return home next week. The correct drawing is a mark-up used by Henley’s contractors and clearly shows the agi pipe connected to the 4 silt pits.