epsilonGreedy

That was a newt in @Onoff's diagram! He needs to enroll at art school.

Do you have any idea what this diagram will do to my sleep quality over the next 20 years. ?

Pleased to hear this. My own hunch was that chains of plastic polymer molecules are unlikely to be troubled by a little alkaline in cement. I am far more worried by four legged furry creatures with sharp teeth and a proven interest in plastic.

This is my concern. After empty homes became liable for council tax during the 2008 financial crisis people were motivated to play the "not habitable" game on some technicality. To counter this practice by large house builders there was some Government policy revision and we slow paced self builders were the collateral damage. I wonder if any of this trumps the older case law mentioned by @JSHarriswhich predates the 2008 change.

I found this old thread via a Google search and my question is related so I thought it would be ok to tack this question on here. Question: In a more recent BH thread someone mentioned that blue MDPE should not come into contact with concrete because of the risk of a chemical interaction. Is this true? I do understand the related issue of a pipe freeze risk due to such contact.

I previously thought the council had to be able to demonstrate a property was habitable and key test points were a water supply, bathroom and working kitchen. The problems is can we expect our local councils to obey the law, for example look at how some were censured for using new anti terrorist legislation to spy on parents gaming school catchment area policy. I wonder if my local council is making up policy with disregard for legislation, what empowers them to decree how long it should take to complete a house once the shell is weather tight and then assume a self builder should complete a property on the same timescale of a mainstream pro house builder.

Hopefully they mean professional/trade insurance? Will you still take out self build site insurance? I ask because it is not clear if you want to offload all aspects of site and build insurance to a main contractor or if you just want to absolve yourself from the risk of employing day-rate contractors. I do not see how how just a series of weekly invoices for labour supplied would elevate these guys to the status of main contractor.

My plot is one of three self builds in a cluster and as the other builds are ahead of mine I have been able to observe how eager the local council is to levy full council tax on a new property. The most advanced build was subject to full band F tax even though it was never occupied and 3 months before the developer felt it was ready to market for sale. Last week an inspector parked next to my plot on the private site road and clocked me keeping an eye on her. After visiting neighbour no.2 she came over to explain her presence. She is one of two employees who keep an eye on new developments in a large rural district council. I had volunteered for council tax band A after taking up residence in the static caravan and with the tallest part of my build just 6ft high I felt I was in a strong position to question her about the ground rules for the commencement of full tax. Apparently the council tax countdown clock starts ticking once a new build property is noted to have a roof and windows fitted. The council then decree it should take no more than 3 months to finish 1st and 2nd fix to create a habitable property. After 3 months a demand for full tax is issued unless the property is manifestly unoccupied in which case there is an extra 2 month grace exemption period. I now anticipate OSB blanking sheets remaining in my window apertures for some time.

In my part of the world this would be termed getting someone in "on a day rate". Is this what you mean?

We followed the design provided by the floor beam supplier which showed the short beams butted at the sleeper wall. Apart from the overhang problem is there another reason to avoid butting beam? Avoid a straight flex line, expansion/contraction?

It is worth following @nod's posts on this subject in an earlier thread.

My beams sit on the inner walls plus sleeper walls in a few cases and if the whole design and installation was cut and positioned mm perfect I would have full 100mm cavities. I noticed that the floor supplier rounded up my absolute as-built floor plan dimensions to the nearest 25mm so I assume block & beam floors are likely to overhang the inner wall in places. Someone here said this is to be expected. The largest overhangs are where a sleeper wall runs mid room and shorter beams butt end-to-end. In some cases the 25mm excess in each beam is compounded to create a 50mm overhang. I was just trying to establish if there was some industry tolerance beyond which the installer should trim back the overhang post installation.

I will do the same but the beams also sit on their own dpc, the same is true for the blocks that bridge from the beams to inner wall and the 40mm slips on other walls. In effect the floor structure sits on its own ring of dpc then the inner walls and screeded floor has a second dpc/dpm as a backup. I assume the belt & braces design for preventing damp in a beam & block floor is because a house should last 100 years and we don't want a beam & block floor to develop concrete cancer after 40 years like a 1970's bridge over the M4. My concern is that when the beam-end to cavity gap reduces under 50mm due to the overhang things are getting marginal.

Surface water pooling in heavy periods of rain around the site that then finds its way through the soil to the void. Ponding risk in one part of my site that can reach back to the original foundation trenches where the water can then wriggle through the footing blockwork into the void. Exceptional 1 in 30 year surface flash flood risk that could lead to a flow of water across the site and around the foundation walls below dpc.

Good to hear. The best location for the floor void sump was under the main sitting room 19ft x 17ft where I would not want a sealed manhole cover to access the sump pump, in fact can such an access point be created in a concrete beam suspended floor structure? My hunch is that over multiple decades a simple 4" access pipe is more maintainable than a powered pump. Because the house is raised I actually ended up with a 400mm high space between beams and oversite subsoil which is almost enough for a crawl space, as a result there could a significant flood in the village and my floor beams would still be standing above any water pooled in the floor void. The main idea of the sump drainage pipe is to accelerate drying after the event.

From previous threads here I understand that the beams of a block & beam floor are typically oversized and overhang into the cavity a little. How large can this overhang be before a beam end needs trimming with a large cutter? The concerns I have are: An overhang creates a ledge where dropped mortar can attach and lead to the creation of a cross cavity mortar bridge at which point moisture can transfer into the floor. There is a reduction in cavity width for insulation and hence a larger cold bridge risk.

In the early days post build I might test the sump mid winter out of curiosity after that it will, I hope, be a once in 5 years type event.

I am still trying to formulate plan A. As it happened we had a summer deluge of 1" of rain the day after the floor blocks were laid but before the grouting sealed up the floor. This was enough to cause my sump to fill. I tested the access pipe by pushing a 1" flexible hose down the 4" pipe and was able to suck the pooled water up maybe 500mm but not draw it above ground level. At this point I realized I need to search for a pump that can deal with what I now know is a "negative head".

This sounds promising. I need to take care not to get the temporary hose permanently snagged at the bottom of the sump with extra bits attached at the end of the hose, for example the excess tail of a jubilee clip. There is also a 60 degree bend towards the end of the access pipe where it turns vertically downwards into the sump. I hope a strainer is not required because the whole sump is wrapped in a permeable material to form a 150l strainer.

I expect the water will be cleanish because I dug a sump in the under floor oversite, lined it with a layer of permeable material, then dropped in an underwater soakaway crate and then wrapped it over the top. There should be a 150 liter pool of filtered water to extract.

I can still remember my O level physics teacher rigging a clear water hose from the 4th floor teaching lab to illustrate atmospheric pressure. That makes sense because to start the upwards draw of water, pressure must lowered even further than already caused by weight raised column of water. This sounds like a gotcha because with the use I have in mind I will have to push a 1" hose down a 4" rigid access pipe until it reaches a flooded sump of water at the base of my block & beam floor void.

5000 sounds like a whole mid sized house both inner and exterior wall? You should be getting closer to those SPONS rates for that size of job. Did you impose short deadlines on the quoting brickies? I was quoted £1.30 last year for the inner block wall element of a whole house. Another quote this year was about £2.30 a block for a small 300 block and brick footing wall job. 7n blocks can still vary in per block weight with Hemelites at 15kg then down to 9kg per block for something a little better than an aero crumble mixture.

I was just listening to non brickie pros working on my site as they estimated the cost of my small footing wall job. My garage blockwork is about 6ft high and looking fairly pro, just a few fat perps which I blame on my undesized 435mm wide blocks.

Can a small electric pump suck water up a 1m height differential? I would not be looking for a stellar flow rate, just something slow and steady via a 1" or 1.5" hose. This is for a surface/flood water scenario though the water will be free of lumpy debris or sludge.

I am getting strange looks from the regular building trades and the building control inspector in my quest for a cut garage roof. My motivation is to maximize attic storage space over the integral workshop room and office, I should get 3 m3 of easy access loft storage space as a result.