Our house has a concrete ring foundation with brick veneer outside walls. I’ve just had a couple of tradesmen come for quotes on replacing our water heater with a gas fired continuous flow one. One said that because the access under the house is so poor, through a trapdoor in the bottom of a wardrobe, he’d have to allow 3-4 hours extra labour for the work. At about $60-70 per hour that’s not something to ignore.
He suggested that I get a concrete cutter to cut an access through the ring foundation. That would cost about $150. I don’t think that includes fitting a door after.
Not only would that help with the plumbing job, it would also help with the retro fit of under floor insulation. The insulation guy wouldn’t even quote for that as he said they wouldn’t be able to get the insulation slabs under the floor. The insulation would be polystyrene sheets.
The house was built in 1937, I think. I’ve never seen another with this type of foundation for the walls.
Will the wall survive having part of the foundation cut out? I imagine the hole would be only a couple of feet wide and 18 inches high.
It’s really just about impossible to say without putting a trained eye on the actual concrete wall in question. You need to call in a professional for an estimate.
I would have to see the job before giving any opinions. If you have pics, that would help.
In general, yes you can cut a hole into the foundation wall, and support the house by adding a steel lintel beam above the door.
You are correct, $150 probably does not include installing a door.
Why only “a couple of feet wide and 18 inches high”? Is it a full foundation? Crawlspace?
Why do you want to insulate the floor? Is the space under your house a cold zone?
Where is your existing water heater?
Alternatively, is it possible to install a new and/or larger access from inside the house?
Under the floor is just a crawlspace, only about 18" high and it is ventilated to the outside so it is a cold zone. Climate around here is temperate, i.e. highs of 30 celsius during summer and lows of -5 celsius a few times a year during winter.
The house has virtually no insulation, just a very thin layer of cellulose wool in the ceiling and none in walls or underfloor.
The current water heater is an internal one in a cupboard in the kitchen, very common in houses of this era in New Zealand. It used to have a wetback in the coal range in the kitchen, but that was removed about 30 years ago. I’m pre-empting a panic replacement of it when it fails by having a gas water heater installed outside now. A friend just had to do this but after his electric water heater failed.