Sewage treatment

Although the main pipe that goes from Perranporth to the sewage treatment plant by Cligga goes past the front of the house, that is under pressure and isn’t a pipe we can discharge into.

At the moment Silver Spray is a soakaway !

So, as the house is being “upgraded” we’ll be fitting an on-site sewage treatment plant. These treat the toilet waste and to a level where the water meets the rules to be discharged into the groundwater.

This is what the neighbouring properties all have.

Next door to the east, Ramoth have a Klargester BA 450 BioDisc (now part of Kingspan Environmental) unit, that was installed by Dorset based Environmental Drain Services Ltd.

Talking to Environmental Drain Services:

  1. As it’s a treatment plant and not a septic tank the 7m minimum distance from a habitable dwelling rule does not apply.
  2. You need to be able to, on-going, access the lid to get into it. So you can build decking etc over it, but you can’t stand, drive or put earth over it.
  3. We should be able to rely on the¬†percolation¬†test / survey done for Ramoth way, as this is just next door. It’d be very unlucky for this to not be indicative of the Silver Spray ground.
Talking to Mark at Ramoth, there is not only the Klargester unit, with it’s small power supply, but the outlet feeds into a series of underground trenches, that in their case are closer to the house than the Klargester. These trenches are rock filled to help the¬†distribution¬†of the discharged treated water.


Contractor Contracts

An email in from a buddy who has managed quite a few commercial and larger (multi dwelling) building projects:

The only other things to be aware of and concerned by is the type of building contract to be used. The standard form JCT contracts, I believe, are biased towards the contactor, the ACA standard form was written by Architects and is more balanced.

You also need to think about the level of damages for overrun on the contract. This is slightly more complicated than it might appear. One of the most crucial decisions made by the contract administrator is the issue of the Practical Completion Certificate as this signals the contract has been satisfied.

If there is an overrun, as invariably there is, he has to decide who is at fault and you are in the territory of the famed “critical path”, ie if the delay prevents progress on the rest of the build its on the critical path and who ever caused that delay in culpable. The reason these decisions are important, even for one week is there is a swing for every week by approximately twice the level of damages assuming damages are set at a level similar to the “preliminaries” figure. Prelims are the costs to the contractor of being on site, ie his admin costs. So if damages are say ¬£2000 pw and prelims say ¬£1500pw and there is just one week delay caused by the contractor he is ¬£3500 down. You get the picture it can get very prickly.

Good luck, I am sure it will go well, new builds tend to be easier, provided they are well planned, because there are less unknowns. Keep an eye on any unusual materials and/or bespoke items that have long delivery lead in times and/or are coming from none standard sources as these can be the source of serious delays.

Frame the sea view ?

How about, as suggested ages ago by Jo Brannan, reducing some of the north, sea facing glazing (glass windows, doors, panels) to have more of a frame on the view.

Yes it’s great to have some rooms where it’s full whack the view, where the end side walls, roof and floor are the frame.

But maybe some other rooms have less glazing. Walls are also much more thermally efficient and cheaper for the heating efficiency of the building.

This extreme framing (ie mostly wall Vs small window) works to amazing effect.

The above photo is from

For this endless ocean view, instead of the windows going floor to ceiling, the designer chose to pull the focus tight by using a smaller window. The minimally framed window creates the look of art on the wall and brings your attention to the balance of sea and sky and the subtle gradient of color.

It seems almost any frame, can end up adding to the view:

Second pre-app meeting with Cornwall Council

Today, Robert (the architect) and I had our second pre application meeting with Cornwall Council.

The first pre-app was great. We felt the verbal meeting and post meeting written response were both very positive. They wanted some tweaks / work done on 2 small areas. The first was more that we hadn’t covered that we were making all the considerations we should. We did have it all covered, but this was written up in the pre-application¬†we made. The second was that they felt we could change the treatment of one of the areas to visually improve it.

So this second pre-app was to go over our submitted suggestions and ideas. The planning officer had a preferred option, which, in our view, looks great and lets us crack on with finalising plans.

The next step is to run the general scheme past a few potential builders, and probably a structural engineer and probably a Quantity Surveyor (QS) so that we can confirm it’s all¬†feasible¬†to build and that the budget is sufficient for the current plans and ideas.

Construction (embodied) Energy Vs Operational Energy

My Summary / Conclusion

  • In 2007, 16% of CO2 equiv impact is construction of a building, 84% is operational / in-use.
  • Today the split is¬†roughly¬†20% embodied and 80% operational.
  • The modelling shows that we are moving to a¬†CO2eq (CO2 equivalent) of 38/62% for masonry construction, and 35/65% for timber-frame construction.
  • No significant differences emerged between masonry and timber construction in terms of overall CO2 impact over the 60- and 120-year study periods. The largest difference observed between comparable masonry and timber constructions was 4%.
  • No clear / significant impact of thermal mass.
  • Emissions are cumulative, so 1 tonne of CO2 equiv at the point of construction roughly equals a tonne of CO2 equiv during the 60 year life of a building.

Which aspects of a dwelling are responsible for the largest CO2 impact?

  • Space and water heating have the largest CO2 impact in dwellings.
  • Appliances also have a large operational CO2 impact.
  • In both masonry and timber constructions, the impact of foundations and ground floors dominates the embodied CO2eq impact.
  • In masonry construction, the external walls also have a major impact.
  • Other elements, such as windows/doors and floor finishes, have a relatively large impact because they are repeatedly replaced throughout the life of the dwelling.
    • Waste water heat recovery systems have a 60 year assumed life span (windows and doors – 40, MVHR 15, flooring 10 ….)
  • The embodied impact of services was found to be approximately 5% of impact at 60 years and 7% at 120 years.

Construction Vs Operational Energy

I’ve come across some interesting figures and links to research in an article in the Green Building Magazine (by¬†

  • Embodied Energy – a ticking time bomb (Spring 2012)

In 2007, around 16% of the CO2 equivalence impact was constructing a building.
– This covers the manufacture of materials and components, transport and construction.

84% of the CO2 equivalence impact of a building was down in use emissions.

This data is from

That is why policy to date has been biased to making buildings more operationally efficient.

The article then makes the point that raises the importance of embodied (construction) emissions. Namely that since emissions are cumulative, 1 tonne of¬†CO2 equivalence impact occurs for every year this “CO2” is in the atmosphere. So 1 tonne of CO2 at the start of a buildings 60 year life will have twice the impact of 1 tonne emitted during the building’s life.

The longer a tonne of CO2 hangs around in the atmosphere, the more damage it can do.

So it’s potentially dangerous to focus on carbon-intensive solutions that are installed at the point of construction, so that they reduce the operational emissions.

So, it is best to look for principles, materials, solutions etc. that will reduce both the construction (embodied) and operational energy of a building. So, as it’s often said, the general advice is still to optomise the fabric efficiency of a building before other measures.

October 2011 Update

The October 2011 report by the NHBC Foundation¬†(“Housing Research in partnership with BRE Trust”) –¬†Operational and embodied carbon in new build housing – A reappraisal:

Until now, focus has been almost entirely on the carbon emissions resulting from using homes, but clearly the balance between those operational carbon emissions and emissions from producing and installing the materials ‚Äď the embodied carbon ‚Äď needs to be considered.

This publication explores a subject which has to date lacked a strong and accessible evidence base. It looks at a range of carbon reduction scenarios as delivered through typical house types and estimates the likely impact both in terms of operational and embodied carbon ‚Äď providing an insight into the contribution of different technical responses to the low carbon agenda, including the balance between operational and embodied carbon.

Evaluated Scenarios:

Twenty-four scenarios were appraised, using SAP software to determine operational CO2 emissions and BRE Global’s Environmental Profile methodology to analyse embodied CO2eq emissions.

The research considered the following variables:

  • two built forms (detached and mid-terraced)
  • two construction weights (masonry and timber frame)
  • three operational CO2 performance levels (25, 31 and 40% reductions over¬†Part L1A 2010)
  • two dwelling lifespans (60- and 120-year study periods)
  • varying grid electricity CO2 intensity (to account for the expected impacts of grid¬†decarbonisation).

Extracts from the report:

  • The modelling showed a typical percentage split between operational and embodied CO2eq (CO2 equivalent) of 62/38% for masonry construction, and 65/35% for timber-frame construction.¬†These are averaged figures.
  • No significant differences emerged between masonry and timber construction in terms of overall CO2 impact over the 60- and 120-year study periods. The largest difference observed between comparable masonry and timber constructions was 4%.
  • The modelling showed that space and water heating, along with foundations, ground floors, windows/doors and floor coverings, were the largest contributors to overall lifetime CO2 impact. Appliances were also a significant contributor, but building designers have limited opportunity to reduce these emissions via their designs.
  • The typical split between operational and embodied¬†CO2eq in new build housing has been taken as 80% operational, 20% embodied, a position largely confirmed by recent studies[1]. However, within the context of future Building Regulations requirements ‚Äď which are expected to tighten to the point that new homes will be significantly lower in CO2 from 2016[2] ‚Äď operational CO2 emissions¬†are set to fall radically. This means that embodied CO2eq emissions will become increasingly significant in terms of the percentage they contribute to the overall CO2 impact of new build dwellings. In addition, typically the more energy efficient a given house type becomes, the greater the quantity of additional materials required to construct it (eg additional insulation, more services). There is also potential that such additional materials (eg renewable generation installations) may have particularly high embodied CO2eq levels. Both these considerations suggest that, as operational CO2 emissions reduce, embodied CO2eq emissions will increase.
  • The replacement of services and other building components has a direct bearing on both operational and embodied CO2eq emissions across the 60- and 120-year study periods.

Assumed lifespan of construction elements:

  • The proportion of embodied CO2eq in masonry construction was found to be higher than that in timber construction. However, this difference was relatively marginal, the maximum difference being 4%. This is because, other than the¬†walls, the majority of building elements were similar in both the masonry and timber constructions modelled.

Which aspects of the dwelling are responsible for the largest CO2 impact?

  • Space and water heating have the largest CO2 impact in dwellings; this remains significant in all scenarios despite diminishing slightly as designs move from 25 to 40% CO2 reduction.
  • Appliances also have a large operational CO2 impact, although dwelling designers have limited ability to help achieve reductions in this area.
  • In both masonry and timber constructions, the impact of foundations and ground floors dominates the embodied CO2eq impact.
  • In masonry construction, the external walls also have a major impact.
  • Because both of these areas will last the lifetime of the dwelling, they should be considered at the design stage when seeking to reduce the overall dwelling CO2 impact.
  • Other elements, such as windows/doors and floor finishes, have a relatively large impact because they are repeatedly replaced throughout the life of the dwelling.
  • The embodied impact of services was found to be approximately 5% of impact at 60 years and 7% at 120 years. However, these results should be treated with caution as some aspects, such as controls, had to be omitted due to lack of available data, and the services were not studied in depth during this project.

Did the varying thermal mass levels have a significant impact on cooling?

  • No clear trend was identified from the modelling carried out, with minimal impact from¬†space cooling in both masonry and timber designs.

External Layout

Rob from ra-studio¬†is continuing to come up with amazing¬†architectural¬†and design solutions for the project.¬†Successfully¬†converting my “living requirements”, tear sheets, ¬†thoughts and ideas into something that is really coming together.

As the house layout gets closer to something that will need to be costed up, we need to add in the context of the space in front and behind the house, so I went through my notes and found this magazine page and sketch:

I like the low wall from the patio, for sitting on, then a flower bed, instead of a wall. Central steps that’d go down to the flat grass over the garage roof. I don’t like the drop in height from what will be the lounge.

Interesting to find this early days sketch layout:

  • The idea of the external hot shower being under the stairs down from the rear parking, so you can look out through the stairs at the view. This assumed the stairs wouldn’t be in the ground behind the rear courtyard, which is the current likely and sensible plan.
  • Suggests downstairs utility to include a shower.
  • Small side walls to the living space courtyard. I wonder if these will now be included or not. I’ll leave that for Rob’s input.
  • I’d forgotten the idea of a space for bins on bin day. The current idea, is that there could be a side door from here into the garage.

There is also the “Droskyn Development” planned for the land to the south of the house. Below is an annotated illustration from the thus far proposed plans. This means there will be properties, across a road to the rear of the property.

Proposed Droskyn Development plans - impact on Silver Spray

Development behind Silver Spray is progressing

Despite the parish council voting against the proposal for 31 houses on the land behind Silver Spray, Cornwall Council have voted 10-3 in favour of the development – with conditions.

Tescan Ltd has been granted outline planning permission for a mix of private and affordable homes, including an eco-style subterranean luxury house built into the side of the cliff, that campaigners claimed would be worth more than £2 million.


Fire side seating nook ?

Create a fire side seating (snoozing) with a view nook ?

With the latest layout / design ideas in from architect Rob, this could either go below the wall from the dining area (to the right of the fire as you look at it), or to the left of the fire and so surrounded by glass and closer to the view.

This could fit in well with the idea of a glass corner and the other fire place posts.

Design according to NASA

I’m reading Kevin McCloud’s 43 Principles of Home.¬†From watching Grand Designs I didn’t get this much of an impression of him being aware of eco / environmental / sustainable¬†issues.

Anyway, not related to that, but a great design methedology bit from NASA:

How to Design according to NASA:


STEP 1: Identify the Problem — Students should state the challenge problem in their own words. Example: How can I design a __________ that will __________?

STEP 2: Identify Criteria and Constraints — Students should specify the design requirements (criteria). Example: Our growth chamber must have a growing surface of 10 square feet and have a delivery volume of 3 cubic feet or less. Students should list the limits on the design due to available resources and the environment (constraints). Example: Our growth chamber must be accessible to astronauts without the need for leaving the spacecraft.

STEP 3: Brainstorm Possible Solutions — Each student in the group should sketch his or her own ideas as the group discusses ways to solve the problem. Labels and arrows should be included to identify parts and how they might move. These drawings should be quick and brief.

STEP 4: Generate Ideas — In this step, each student should develop two or three ideas more thoroughly. Students should create new drawings that are orthographic projections (multiple views showing the top, front and one side) and isometric drawings (three-dimensional depiction). These are to be drawn neatly, using rulers to draw straight lines and to make parts proportional. Parts and measurements should be labeled clearly.

STEP 5: Explore Possibilities — The developed ideas should be shared and discussed among the team members. Students should record pros and cons of each design idea directly on the paper next to the drawings.

STEP 6: Select an Approach — Students should work in teams and identify the design that appears to solve the problem the best. Students should write a statement that describes why they chose the solution. This should include some reference to the criteria and constraints identified above.

STEP 7: Build a Model or Prototype — Students will construct a full-size or scale model based on their drawings. The teacher will help identify and acquire appropriate modeling materials and tools. See the design brief for a sample list.

STEP 8: Refine the Design — Students will examine and evaluate their prototypes or designs based on the criteria and constraints. Groups may enlist students from other groups to review the solution and help identify changes that need to be made. Based on criteria and constraints, teams must identify any problems and proposed solutions.