saveasteading

Handy hint. Of course keep the excavated hole as tight as possible to minimise costly backfill and reduce earth settlement in future. But if you can't avoid a bigger hole, esp sloping sides, then you can minimise concrete and gravel backfill with the use of a board or a cladding sheet. Gravel against the tank, earth behind, pull up and repeat.

Check the instructions precisely. I had a flooring company fit one over a floor (150 concrete) . We put in more and more fans and heaters and dehumidifiers for 2 weeks as the dial was not dropping. Then the flooring company explained that the box being sealed means the numbers stay high. It was OK. That's a bit vague I know....but do check the procedure.

The tank will only ever have a risk of floating when empty combined with high water table. After installation it will always be full, except on the few occasions of pumping it out. Do tell.

I've had a look at the info, such as there is. It appears to be simply a holding tank with lots of perforation. It will catch and hold the treated liquid ejected if there is a run on baths and flushing. Then it soaks away......nothing happens inside the box. Thus is is not spreading the outfall in the way that a long pipe would. You could as easily build a plastic catchpit with no bottom and optional holes in the side, or make it of brick, the worse quality the better. Or wrap a crate with membrane. I guess the big sales points are. 1. It gets buried and carries a load. 2. It is made by a digester company. 3 fits in a driveway. 4.. A bco feels safe accepting it and will not be blamed for any pollution. This being the main attraction? Against it. 1. Small footprint so not dispersing the outfall very far. 2 expense. 3. A pipe system in gravel will encourage further treatment of gunk stuck to gravel. In summary it's just a soakaway so is encouraging a reduction in soakaway standards, but will be easy for a builder, and the bco may feel able to accept the nice certificate for the file.

I've only ever used Marsh,4 times. The effluent always looked and smelled clean.... but I washed my hands. The new Marsh tank has improved numbers. Granular backfill easy too .... what concerns you.

You could theoretically add a foot or so of pir to the wall and retain your headroom.

Farmers should plough across the field, but don't, and prefer the water to run away. How about a seasonal pond? The surface area promotes evaporation. I put one in for our offices. Full in winter, dry in summer. Nature adapts.

I've encountered several crooked epc 'consultants'. What rating do you need? Under questioning, disguised as naive chat, it was clear that they were genuinely ignorant of the science and building practicalities. I did wonder where they emerged from? They did not like real construction info either. I think they had bought or rented a very, very primitive assessment template. Is the wall single skin, double skin or cavity., insulated or not. And so on. I had one that we told we had upgraded a party wall.....not interested....went down as single skin with plaster both sides. So we got a C that would have been B. C is good enough for anyone he responded. I'm pretty sure he would have changed tick boxes to get us a C whatever. My suspicion is that many a rental has such a fraudulent certification. I would never conciously use them, but am not in need of them either. I don't blame the councils. They are being tricked as much as anyone. If I was still involved in the industry I would be meeting builders, bco and other officers at council workshops...i always found most of them to be interested....but I'm not. Cheating is bad, but so are stupid rules. Shop around?

For caution, just use a brick. It will grind off the tiny high spots to the surrounding level with no risk. Or buy an abrasive stone....but usually a brick is better I think.

What is inside the tunnel? I'm guessing filled with plastic shapes / nodules as found in pond filters. Ie maximum surface area for crud to stick to for bugs to consume.

Nope. Except sizing the chambers. Bacteria wouldn't understand a complex system.

Yes. But gravel does that and, I think, better . It's the same principle as gravel in trays for car parking....no oil interceptor required. The oil, or the stp discharge runs on and into the gravel and coats the very large surface area. Micro-organisms consume it. So gravel around perforated pipes is my choice...Best and cheapest. I've done this for very testing facilities. 1000m2 office, 4 team sports pavilion plus others. No problems ( I would have heard). The crate with media may be viable where there is no land for French drains. But the flow out of an stp is nearly clean...when I've taken a non -technical sample it has looked clean and had no smell. I vaguely recall one installation (by others) needing maintenance but it was the wheel-going-round type that had stopped going round. In summary. The crate ticks a box.

Does it need a sole plate? There is no provision of levels required. Swing up the panel, screw to the floor, pack to the ceiling as @andyscotland. a few blocks might suffice fixed up....somehow. Mineral wool better than foam board for sound reduction, but the gap will be helping a lot too. If this is a party wall there shouldn't be any damp.

Efficiency of stacking can delay use til the next meal. That will save more energy, and water, than anything else. Apparently long, smart programmes are also efficient. I don't know what is smart? Perhaps how mucky the water is. If you get it fitted by the delivery guys, double check after they've gone and check for leaks. They arent employed for their plumbing skills. My last 2 have both leaked from the water connection causing great problems. In each case it was simply mis-threaded.

Love the drawings. Almost art. Making on the ground is normally far easier, esp for getting a vapour barrier on the back. BUT in a tight space probably not as it would be difficult to swing up.

Ok so I'm getting mixed up by the terminology now. Drainage field in the English regs is just french drains. So use French drains but call it a drainage field. They call it a drainage field for the small amount of liquid from an stp, but soakaways if it is rainwater. What I say still applies.

Because its confusing. Solar complicates the calculation. Without it, the tank water should be cheaper. With it? Will the team work to the required times? Let us all know your decision, with reasoning.

No it doesn't. It is a fancy option when a soakaway won't work. So you have good percolation figures. Too fast at one location which in theory means your treated water runs away too fast. 1. The stp manufacturers have long stopped claiming you could drink it, but it shouldn't be nasty so a soakaway will allow bugs to treat it further then it dribbles slowly to the aquifer, among the natural water containing worm and rabbit remnants etc. No harm. 2. If it ran away too fast it might open a stream and stop filtering it. So at that area of fast percolation, rather take drainage elsewhere or close the French drain off...use umperforated pipes to bypass it. 3. A drainage field would be pointless as your French drains are underground and self emptying. I think some people say drainage field wrongly, meaning a soakaway system. 4. As another current discussion, I like French drains rather than crates. They spread the water and are easy to lay. The gravel surround continues the treatment as any stuff sticks to it and is eaten by bugs. The formulae tend to be verrrry conservative. I can't suggest putting in half as i don't know your site circumstances. Perhaps build it in phases for programming reasons and look out for any problems.

I haven't done one, or had it done, for decades. Can you describe the ground? See the soil deviations in that nhbc guide. Is it clay / silt/ sand or whatever. Soft / hard? Use everyday terms

Idea. I have lights in some walk-in cupboards that come on when the door opens...but they are presence detectors, not on door switches. Another in the kitchen has the option of lifting off as a manual torch. They simply stick on the wall, so cheap and easy. I had a client once who made a contractual claim, including that the toilet light was always on. In front of the adjudicator, I asked if his home fridge had the same problem. Nobody quite laughed.

That's cheered me up.

I remember there being lots of kits on sale for this from b and q etc. We did it once and were underwhelmed. They haven't appeared on our dream kitchen designs since then. I think the issue is that when shelves are packed, a light isn't much help. Instead put an extra ceiling light pointing at the wall cupboards, and a torch in or near the cupboard under the sink.

Well done. It has to be number 2. Your worries are sensible and sortable. A) expense...later. B) upheaval. Meaning nuisance? It can be less than you might think. Digging the pit is the biggest issue. But if you have access it's ok. the tank is manhandleable by 4 people OR digger. C) risk of obstruction. Your new drain takes priority. Dig the whole trench and pit from house to tank before laying or connecting anything. Pipes move, roots cut. New pipe doesn't have to be deep as there is no load over it. D) maintenace costs are very low. Plus they will be in your control....nothing going in that shouldn't, and no rainwater either. You can study how the tank works and decide if it needs cleaning.....which it shouldn't. You can make uour own test sump for the outflow. The testing kit is eyes and nose. The new Marsh tank supposedly uses less power and works better, but costs more (£300?) : your shout. Btw i have an ancient brick cess tank and have had it pumped out once in 20 years..... also a 3 chamber tank with no mechanicals or power Never cleaned in 20 years. E) Pool stability. A wise concern, but I can't comment. Except to ask what is the line marked "pump"? Why not drain to the orchard? If you use a pump then the pipe is small and shallow. Most people seem to use soakaways smaller than the design rules. I prefer a french drain, and it's easy to extend (phase 2). A) again. Covered in the above. Rain pipe in same trench? You can get big discounts for big pipe orders. Can be diy with mates. BUT I think BCO should be involved.

Probably about ...I don't know. Guess 300? 2.2m high min, to 8m max. Mostly me drawing or standing watching, and seldom wielding the stanley knife. I'm maybe missing your point. What I mean is that a fire would not spread under that even without intumescent mastic. I guess a really poor sole-plate fitting where you could see light through, might be a slight risk IF the blaze was intense and there was pressure forcing air through and a floor level fuel source. I've been informed that tests show that a 3mm gap between plasterboards onto stud, does not create any risk. But if there is sealer, for a few more £, then everyone is happy.

All very interesting. Background then serious suggestions. This will overlap with what you already propose and others suggest above. Credit implied! I sometimes come back from trade shows, all excited about a new product and way of construction. I take some convincing and expect am a pain to the reps of most things. There have been lots of these screws on show recently. But my career is based on build-ability, function and cost. Although qualified myself I always had an independent SE practice do the final calculations. That was also a reality check before construction. Once new methods were established and proven I would tend to make it standard. Often the SE would admit they hadn't wouldn't have thought of my proposal and didn't realise the cost/ buildability advantage. ie they were not contractors, aware of costs. But the reality generally did not appear innovative to non industry persons. To the point.... You are proposing a concrete ring beam good. I've seen another discussion with steel. I've looked at these piles for a decade or more. Mostly they appear to be sold through franchises of people who offer only this....ie not neutral. I'm sorry to say most of the reps don't know much. Despite this I have tried to design solutions using them, but never selected them....on cost and function. I see them as good for temporary buildings on bog or shallow landfill. Issues? As the above correspondents. Plus the trees and wildlife can flourish under your building. Your ground is OK. But the trees require foundations to about 2.4m. My gut feeling is to build concrete pads (mass filled, easy and cheap) at all corners and about 10 intermediates. Span the perimeter between them with a concrete beam. Maybe down the middle too. This can be poured insitu or bought in ( I've done both, to suit the circumstances ). You can then floor out any way you like but I suggest beam and block. Perhaps planks. Test both designs for cost and access. No wildlife below. No steel or other metal to corrode. The whole building solidly on good bearing and below tree influence. This can still be regarded as innovative if that appeals, while not worrying the authorities. Cost? Much the same as with screw piles. Maybe less because local builders can do this. It is a suitable diy process too. But it will last 200 years, get building regs, be insurable, be saleable. And not have trees, worms and rabbits flourishing underneath. Questions and counter arguments welcome.