Cristobal Cristo

In this case it may be sufficient. Is it a grid on both sides of the slab - upper and lower, what spacing? Dedicated slab will give you additional support that will distribute the weight or the slab.
If you have a choice II would suggest to have it close to the bathroom/living room area as sleeping in colder air is great, but bathing not so much - at least for me.

Mike,

A dedicated slab is a good choice as mobile home slabs will be usually minimally thin and insufficiently reinforced (if at all).
How do you want to radiate heat through 4" space?
Centrally located RMH should heat the key areas in a light mobile home. If you shared the plan we could help with heater placement.

I already commented on this issue stating that there exist quality differences between various IFBs, but now I'm thinking that they should not be used in the wood flame path.
Two vendors/manufactures that I inquired about IFB use in flame path said it was OK, but at the same time it's rather obvious that they are not intended for wood flame path:

1. IFBs are rather new invention, established in industry in the 50s.

2. Industry uses natural gas, propane or electricity to melt, crack, kiln fire.

3. If wood is burnt in biomass power stations or incinerators - high alumina hard bricks are used (I read some paper), because amount of fluxes and detrimental substances is high.

My electric ceramic kiln is lined with IFB-26, but it's electric and only I converted it to propane and propane exhaust is super clean compared to wood and I use it maybe 10 times per year only, so I may not be able to notice any deterioration.
I just read that IFB/propane kilns may have longevity of 1-5 years in high use environment. High use for ceramics firing would be once per 3 days, because cooling to less than 50 C (safe for glazes) takes me around 40 hours. For quick raku firing (objects are removed hot from the kiln) firings could be more frequent with much more thermal stress.
Masonry heater will be probably fired for let's say 4 months, so with one fire par day it's 120 firings - equivalent to once per 3 days kiln use schedule. However the fuel is wood with chlorine (bricks don't like it) and various fluxes. Also the temperature in properly built riser is equal and turbulence much higher than in a kiln.

So it looks like IFBs in wood flame path are really being tested by us. I'm really curious about performance of IFB risers built by others.

I have checked some estimates to determine the percentages of land areas that would definitely not support vegetation (without great effort):
Tundra: 9%
Alpine climates: 3%
Deserts with less than 100 mm precipitation: 10%
Ice capped land: 10%
So it's 32% of land where growing anything would be pure misery - if possible at all: maybe some cactus on the desert, some berries in tundra and Alpine climates, but it would not feed anybody in significant numbers.
There are more land types (than those listed) where attempting to grow would be probably waste of time or resources. It would be deserts with precipitation between 100-200 mm (another 9%) and it's too low to support anything meaningful without irrigation, harsh cold steppe climates with very short growing seasons, etc. There are also tropical forests that we want to protect due to biodiversity - another 12%.

I have added coarse sand that I was using for building but it got mixed with the soil, so I needed to do something with it. When added to my clay loam the first time I was able to grow onions to an extent sufficient to enjoy the bulbs (and not only greens). Some people claim that mixing sand into clay will make it even harder, but it worked for me and loosened the soil so I can work it in summer without using pick axe. I will be adding more to other spots.

I think every land can be made suitable, but with an investment that exceeds the gain, otherwise people would be farming these lands for millennia, but they do not. The mighty force to find/produce food is also mother of inventions, but it did not help. It's a different thing to grow something that grows at all - some greens, herbs, fruits versus growing staples that actually can feed a family/nation: tubers, grains, legumes. There are countries that just can not grow their own food and food security is always a priority. If they did not find a way to do it, it means something (despite the incompetence of most governments, foreign lobbying, etc). Maybe the numbers are different, but most of lands in my opinion are unsuitable. There are a lot of mountains, deserts, tundras, taigas, ice caps, various bad lands on the planet.

May, I have plastic irrigation and risers. Stainless pipes are in the house and around the well.
Try to purchase pipes in 20' pieces, they will be much cheaper than short ones. Also try facebook marketplace.

May,

I was talking specifically about house plumbing.
Most fittings are available in NPT thread and butt-weld versions. Welding allows you to use thinner/cheaper schedule 10 pipes. Threaded pipe needs to be at least sch 40 (enough thickness to cut the thread). I use both. Frequently I weld sch 40 half nipple to sch 10 so I can use thinner pipe and have the thread.
For sewer I needed to cut at some sngle to develop grade.

I have imported 1 ton of pipes. Even after, freight, brokering, tarrifs, trip to the port, it was still more than 2 times cheaper than the same imported stuff here. Maybe it doesn't sound permie-like but it's top quality and will last for millenium (rather longer), so actually very permanent.
Fittings I purchase locally (company belongs to Fergusdon now, they have greatest selection and prices) or some deals on ebay.

Regarding stainless for irrigation, I would start with stainless risers. Plastic risers already got destroyed 4 times by my animals and me on the tractor.
Riser, threaded elbow and 3/4" male NPT to hose barb would be a good start. Undreground supply pipes next.
Black, flexible lines would be most difficult to replace. Emitters are only plastic, but not everybody uses emitters.

I use stainless 316. Some pipes welded, some with fittings. Maybe not 100% perfect, but almost. Less resistant (without 3% Mo) 304 or 18/8 is used for kitchen utensils. 316 is used for bone implants. Sometimes on 304 that was left to elements I can observe thin, tiny spots of rust. Never on 316.
It's not cheap but cheaper than plumber+cheapest plastic combination. I usually cut the pipes, fittings myself, sand, bevel and clean and someone welds for me (with my equipment) as I don't have a good hand for circular welds.

Emma,

Chicken will not only destroy young plants but they will peck into all cucurbits, tomatoes, low hanging fruits (figs, grapes). They will keep eating swisschard and spinach and any other greens that they find palatable. One time they climbed my olive tree and they were visiting for few days until no olive fruit was left.
Some chicken will squeeze through 6x6" openings in the fence, but do it rarely. Smaller openings are safer.
When they go to my orchard they like to scratch around irrigated trees/bushes and they frequently disconnect the thin hoses from emitters.  If I don't spot it, a young grape or fig may not get directed water for three irrigation sessions and the plant will die.