I had a comment on an old post that included a question. Replies can get lost when the post is from way back when, so I thought I'd answer it in a new post instead. Maybe it might even be helpful to someone else wondering the same thing. :)
Q: I do have a question about your mulch near the slab of your house. Do you find moisture a problem being in contact with the slab? And do you have direct sunlight to the front of your house? I love the vegetation in front of the house, but I'm getting advice from pavers not to put anything near the slab. ( due to the fact I have no direct sunlight to the facade either).
A: I've heard a few people say that their builder told them that they shouldn't construct garden beds directly against their house, but these are some of the points we took into account when making decisions:
- Our garden beds, including mulch, are below the damp course in our brickwork. Building anything or heaping up soil past that point, especially over the weepholes, is a big no-no.
- Termites aren't generally a problem in this area. If you're in a termite-prone region, you might want to get expert advice and/or install a reticulated termite barrier before doing any landscaping against the house. We never saw a termite in 22 years at our old house, and termite damage is pretty rare around here, so we're a bit blase about it.
- The soil here is extremely reactive (which means it expands and contracts a LOT depending on rainfall), but our slab has been engineered with that in mind. We paid a premium for the slab to be upgraded to Class-whatever, so it had better be damn well built to withstand a bit of moisture....
- If you use the right kind of mulch and you've prepared your soil well, the soil ought to stay damp, not the mulch. That's a whole other post though.
- What the hell else are you going to do around the edge of the house if you don't build garden beds? Circumnavigate the building with solid concrete? Over my dead body.
- Apart from said concrete, anything you put against the house will get damp in wet weather; soil topped with mulch, soil topped with pebbles, toppings or gravel, whatever... consistent rain will penetrate the top layers and it'll be wet underneath.
The house has been completed for two years now, and we've had very minor movement - probably as much from the frame timbers shrinking as the slab moving - resulting in some small gaps opening between walls and skirting boards and walls and cornices in a few places. All perfectly normal and nothing a bit of No More Gaps and paint can't fix.
I think that as long as you make sure your damp course is above the soil/mulch line and your weepholes are clear, you should be fine.
As for the direct sunlight thing, yes, the front of our house faces south-east, so it gets morning sun. Depending on climate, especially if you have high rainfall, a true south aspect might be a different story.
Of course, I'm not a builder or concreter or any other kind of expert, so taking my word for it may not be the smartest move you've ever made.