One of the joys of living in an old house is some of the problems that you encounter. One of which is rising damp. Since getting the house renovated nearly three years ago we did not touch what has become known as the “old part of the house” – which comprises the two front bedrooms.
This meant that our teenage daughter has been sleeping in a pretty rubbish bedroom for the past couple of years. So with a bit of pressure from mother and daughter it was finally time to tackle the rising damp issue.
First up I contacted a number of rising damp “experts” that I found online each of which came up with a different solution to treating the rising damp problem. These varied from “all you need is a dehumidifier and a couple of extra underfloor vents” (which we already had both of) to “its not rising damp its falling damp get your roof checked”.
There did not seem to be any consistency in either, the cause of the rising damp or the remedy to fix the rising damp so the search went on…
I contacted a couple more Sydney rising damp companies and two of them suggested injecting the walls with a damp proof course and installing sub-floor fans. So we decided to go with the cheaper of these quotes – however 6 months later I could still not tie him down to a date of when he was going to start the work.
Tell him he’s joking son!!
Part of one Quote we received
Meanwhile, the pressure was building at home!! So I revisited their quotes and after a bit of Googling I discovered the product they were using was Tech-Dry DPC Cream.
Made in Australia, Tech-Dry DPC Cream is an innovative water-based silicone cream. Its highly concentrated active ingredients contain over 80% active silicone, which forms a permanent damp-course within masonry walls.
How does DPC Cream work?
Once injected into the walls, the cream penetrates the bricks or other masonry substrates above and below the mortar bed. This then form a permanent polysiloxane damp-course within the treated wall to prevent rising damp.
After watching the videos on the Tech-Dry website I was fairly confident I would be able to tackle this project myself. I ordered a 5 litre bucket of the Tech-Dry DPC Cream online and was surprised to find it turned up the very next day – although I do live in Sydney where they are based so may not be the same for every region.
I then went to Bunnings to buy the required drill bit and Kennards tool hire to hire a proper masonry drill as the large drill bit would not fit my drill.
First up was getting the skirting boards off, turned out was easy enough and I managed to get them off damage free.
Step 2 was trying to gauge how deep to drill the holes, so I found the subfloor air vent and stuck the drill bit in far enough to touch the air vent, knowing that if I went deeper I would go through the wall. Hope that makes sense!!
Turned out that the drill bit I had purchased was not long enough as the walls were actually a lot thicker than I had anticipated.
Step 3 get drilling…
For the front bedroom I did the holes internally but because there are fireplaces in both bedrooms I figured that as I would not be able to drill behind them I would be better tackling the issue from the outside.
To find the right level on the external wall I measured inside from the top of the window frame to the floor.
I then went outside and measured the same distance on the outside wall. If you don’t have a window maybe you could use the internal air vent.
Once I knew the height I then put a long piece of wood against the wall using a spirit level to ensure it was level. I then drew a pencil line on the wall so this line was the level I had to drill along.
Next up I marked 80mm on the spirit level and marked the walls with a dot where I needed to drill each hole I found this much quicker than measuring each hole one at a time as I did inside.
You learn as you go!!
All drill holes pre-marked..
Next step was to get drilling…
The thing about drilling is that you get lots of time to think and ponder – so I thought back to what one of the “damp experts” mentioned about falling damp and I figured that if this product can treat rising damp surely it would also treat falling damp also.
So I called Tech Dry customer service and he confirmed that it would work the same way – so up on the ladder and drilled holes internally and externally where there was an issue.
After drilling and before injecting the Tech-Dry DPC Cream you need to vacuum out the holes to ensure that all dust and residue is removed. So off I went back to Kennards to hire an industrial vacuum cleaner for a couple of hours.
It would not be worth the grief if I had broken our vacuum cleaner doing the job!!
Next up is the sexy part of the job – injecting the damp-proof cream into the walls.
First up is getting the Tech-Dry DPC Cream into the pump. I just bought a basic pump for $22 from Bunnings rather the one from Tech-Dry and the all-important funnel. On first appearance, the Tech-Dry DPC Cream looks like a cross between Greek yogurt and cream cheese.
The whole 5-litre bucket will fit into the pump. In the video below you can see how it works, as I spilled some on the concrete, it has created an oil like barrier on the ground – this is what forms the damp proof course and stops the moisture.
When injecting just follow the instruction video on the Tech Dry website –
- build up the pressure in the pump
- insert nozzle into the whole
- remove slowly until you can see the white cream
A week later I re-injected all the holes again just to be sure to be sure.
All up costs:
DPC Cream 5 Litre x 2 = $792
Freight = $40
Goggles = $5
Dust mask = $5
Drill bit =$36
Drill Hire =$77
Vacuum Hire = $80
Total = $1980
Savings based on quote $1650
Time Taken: 1.5 days
If you have your own tools or can borrow them this will be even cheaper plus you would save time as I lost a few hours in getting & returning tools to Kennards tool hire.
Also I covered a lot more walls than the 9m in the original quote that I received so the savings would actually be more.
Footnote: I did run out of cream as I misjudged the depth of the holes plus I did extra coverage as well as extra holes for the falling damp, so I had to order another bucket of the cream. (Again delivered the very next day) I also did a second round of injections.
So best to get your measurements right as will save you extra freight etc in the long run.
In the next post I will cover installing a sub-floor fan.