The cost of damp proofing and remediation work can vary depending on factors such as the size of the affected area, the extent of the damage, and local labor rates. However, as a rough estimate:
1. Injecting a damp course for 4 meters on both sides of the affected corner: This can cost anywhere from £300 to £800 per meter, so for 8 meters total, it could range from £2400 to £6400.
2. Installing trickle vents on two windows: Trickle vents typically cost around £50 to £100 each, plus installation fees, totaling approximately £100 to £200.
3. Hacking off and re-rendering affected areas with waterproofing: This can range from £50 to £100 per square meter for hacking off and re-rendering, plus the cost of waterproofing materials, potentially totaling £1000 to £2000 for both rooms.
4. Re-pointing the affected area of the brick wall: Re-pointing usually costs around £20 to £40 per square meter, depending on the extent of the work, so this might amount to £200 to £400.
Overall, the total cost for these services could range from £3700 to £9000 or more, depending on the specifics of your property and the contractor's pricing. It's advisable to obtain multiple quotes from reputable damp specialists to ensure you're getting a fair price.