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Mid Terrace 1950 (Brainstorm) G#42526

Mid Terrace 1950 Brainstorm

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About:

Helpdesk:

  • HiiGuru Ask an Expert 30 minute video call between a customer and BrianSpecMan taking notes and follow up additions to those notes with some analysis.
  • (PS indicates new information not discussed in call)

Prior information

  • Drawings with annotation by customer, elevations, sections, floor plans supplied by customer

To Client

  • I do not currently carry any Professional Indemnity Insurance (PII) especially post-Grenfell fire it is difficult to get quotes especially because of my specialism in environmental construction.
  • I am now a ‘man of straw’, not worth suing.
  • I have 50 years’ experience in construction and 26 years focussing on environmental construction.
  • Your own designers may decide to ignore all my suggestions and do what they know and feel confident with.
  • But you are the Client, it is your money that is being invested and you should have some say in the matter.
  • Learn as much as you can so you can confidently question your professional’s decisions.
  • May the force be with you.

HiiGuru Online discussion

  • They have previously been working with another HiiGuru on interior matters.
  • What follows is my remembering of the topics discussed, recording them and adding some more detail and adding links to some of the issues we discussed.

Advance Notes:

  • 1950’s style two storey mid terrace, no central heating
  • Considering Air Source Heat Pump (ASHP) v Gas Boiler and domestic hot water cylinder
  • Planning to start work Mid July
  • I asked to see outline specification or annotated drawings
  • I did see the set of plans sections elevations drawing set at a pdf (noted as ‘for Tender’) in advance but we did not revisit it during the 60 minutes online discussion, and I have not critiqued it thoroughly.

Discussions:

  • 17th June 2025 online call
  • Because of some of the issues I detected in the drawings (discussed below) I asked if they had a contract in place.
  • They may have tendered but no decision yet.
  • They had not, so there was time to potentially change some material choices and avoid some potential risks.
  • A challenge was that tenderer(s) are unfamiliar with and not included for ASHP leaving some scope for finding the right hot water and heating technologies then adding them as specialist installers to be facilitated, accommodated and coordinated with/by the eventual Main Contractor.
  • How do you find a specialist services installer: approach the manufacturer or the supplier and find their trained, approved or accredited installers network.
  • Or go to Microgeneration Certification Scheme (MCS) database for manufacturer’s products and installers.
  • Pay the extra monies to get a competent installation.

Domestic Hot water and Heating

  • UK Government is encouraging all to move away from Gas towards electricity (mains electricity is fed with increasing amounts for renewable energy and is lower carbon than mains gas; but remains inefficient to produce and distribute; and expensive for consumers to use).
  • Electricity price increases are not restricted by Government watchdogs, so will continue to increase in costs.
  • Aim to use electricity wisely, efficiently and effectively.
  • When a building is well insulated then hot water becomes the next biggest energy consumer.
  • Insulate all hot water and heating pipes everywhere before making them inaccessible by covering over or enclosing.
  • Consider shower wastewater heat recovery service, shower wastewater preheats cold water before feeding the hot water cylinder
  • Consider adding Voltage Optimisation (VO) before the consumer unit/meter so you only pay for what you use.
  • Consider switching to Octopus Energy (now or later) advise them of your plans, to optimise signing on.
  • Buy and sell electricity to and from the grid at optimal prices, via Octopus.
  • If using ASHP then feed it with lower carbon renewable energy (RE) from Green Tariff supply or PV panels on roof.
  • Locate ASHP as close to the building as possible to reduce length of insulated pipe runs.
  • ASHP can benefit from being in a ‘hot spot’ a sunny corner bathed in summer and winter sunlight or in an attic.
  • Excess energy from PV panels in summer goes to top up mains and adds credit in your account to pay for mains electricity use in winter.
  • ASHP grants are available from UK government
  • Place and disperse PVs to get shadow free sunlight morning, midday and evening
  • Size and quantities to suit demands and supply to mains using as little battery capacity as can be avoided by design.

Insulation first v repairs first

  • This is relevant to ASHP
  • Whilst many of us argue improve insulation to reduce demand first, before adding ASHP; another priority is being suggested.
  • Seek out all anomalies, repair and improve exiting defects, windows, doors, roof lights and building fabric, first.
  • Including: weatherproofing, airtightness, thermal bridges, air leakiness by adding seals and grommets around services entries, etc.
  • But do not block up air passages associated with suspended ground floors or pitched roofs keeping them condensation and mould free and structurally sound.
  • This alone can make a significant difference to energy bills before adding ASHP or other energy technology
  • ASHP are increasingly argued work well in a carbon reduction capacity if fed with RE whether the building is well insulated or not.

Windows

  • Upgrading windows might also include replacing existing glazing with double glazed sealed units (DGSU) triple glazed (TGSU) or vacuum insulated glazing (VIG)
  • They offer increasing acoustic insulation, thermal insulation, thermal comfort, low emissivity, especially relevant to radiant heat sources (Underfloor heating or infra-red radiant heat ceiling panels)

Ventilation and moisture management

  • If you add insulation, then moisture management becomes increasingly important.
  • Consider whole house Mechanical Ventilation with Heat Recovery (MVHR) with summer bypass and smoking boost button if you are smokers.
  • Consider Passivhaus accredited MVHR
  • When adding attic rooms this makes accommodating the central kit the distribution pipes challenging.
  • Or if whole house MVHR is not practical there are single room (bathroom, kitchen) through the wall MVHR systems available from Redring, Ecological Building Systems or Partel UK.
  • Passive ventilation can be achieved with rooflights allowing cross flow on the one floor if there are no walls blocking the pathway between rooflights
  • Passive stack ventilation can be achieved when the staircase forms a chimney from ground floor to attic, and any enclosing doors can be held open.
  • Windows or doors and rooflights need to be open to get air movement working.
  • Perimeter wall vents other than windows can be incorporated as part of cladding or with windows; including insect grilles to prevent them entering; secure construction to prevent robbers entering; insulated opening panels equivalent to the wall’s U value rather than the window’s U value.
  • These are likely to be bespoke I am not aware of any off the shelf products or manufacturers.
  • ASHP, MVHR equipment need to be located close to external envelop to reduce length of (always inadequately) insulated pipe runs, ensure space for access to replace MVHR filtres
  • Consider pipe and duct runs in relationship to structural floor and roof timbers

Other options Internet of Things

  • Domestic Hot Water using Mixergy ‘Internet of Tanks’ internet connected Hot water Cylinder that draws energy when prices are lowest, or they pay you to take it (mostly at night, off peak)
  • Mixergy have many options about where its energy is sourced: ASHP, Mains, Solar PV, etc.
  • Unlike regular cylinders with the immersion heater at the bottom using eddy currents to warm the full height of the cylinder, demanding lots of heat to create a full cylinder of hot water; Mixergy well insulated cylinders have the immersion at the top only heating as much of the top water as required; without making eddy currents and the hot and cold water remain distinctly stratified.
  • There are heating boilers that do the same but store energy in a wax or salt at times of low tariff at night for heating the house during the day.
  • Some manufacturers use wax thermal store, but I have heard unreliability associated with one product.

Gas Boilers

  • Are more sophisticated and modular in nature, plumbers cannot fix them, they swap out parts until they find the culprit
  • There are still grants to upgrade a boiler, confusing government policy.

Roof construction, insulation materials choices

  • Ground floor pitched roof: pitch looks too low for the roof tiling indicated, worth checking if any precautionary measures are applied.
  • Dormer Flat roof: Optional methods (EPDM v 3 layer built up roofing, different thicknesses depending on materials chosen) suggests contractor design in a general contract, will there be a contract and will is include Contractor Design Portion (CPD)? pricing becomes ambiguous and prone to financial abuse.
  • EPDM is much longer life expectancy than 3 layer build up felt roofing.
  • The dormer flat roof joist zone is empty so winter heating can escape into this zone and dissipate instead of warming the occupants, this void should be filled with insulation.
  • Plastic insulation will permit summer solar radiant heat to enter the roof space and rooms in the roof, once the heat is in it cannot readily escape via conductivity through the same plastic insulation; thus exacerbating summer overheating.
  • Avoid using plastics insulation in flat and pitched roofs.
  • Avoid stone, glass, blast furnace slag mineral wool for the same reason.
  • Consider instead insulation with high density, conductivity resistance and specific heat capacity to resist solar radiant heat in summer and conductivity heat in winter.
  • Consider medium density squeezable wood fibre insulation in dormer flat roof joist space and pitched roof rafter space
  • Consider also high-density rigid board wood fibre insulation above or below joists or rafters
  • Many of the manufacturers offer complete systems of insulation board and moisture permeable internal finish.
  • Other insulation materials that resist solar radiant heat:
  • Cork
  • Cellulose fibre flake (recycled newspaper)
  • Other bio-based plant-based insulations

Client supplied materials

  • Annotation suggests timber floor is provided by client, but it is not clear who is fixing it, pricing becomes ambiguous and prone to financial abuse.
  • 10 mm floor finish is a bit thin for hardwood flooring so Engineered timbers may be necessary, but may not be available this thin?
  • If client is supplying the materials, they take on responsibility for fitness for purpose and merchantable quality.
  • Moisture content becomes an important issue and if the timbers are wrong moisture content and then fail in use then the client takes on some responsibility.
  • There is also a chance of mismatching quantities available, with an allowance for offcut wastage, and matching room sizes.
  • If the same material is to be used throughout, then appearance matching from one batch of materials can become a challenge.
  • Consider Architectural Salvage yards as potential sources of older durable timbers in the quantities required.
  • com is the UK gateway to the UK salvage yards with searches across the many yards in one place.

Reclaimed Aesthetic

  • Grand Designs Live have exhibitors who display artisan handmade furniture made of salvaged materials and components
  • Ranging in style for reclaimed airliner, through steampunk to jukebox.

Kitchen

  • There are second hand kitchen suppliers
  • theusedkitchencompany.com and others
  • Client’s partner is a chef and may well want a stainless-steel kitchen
  • Stainless steel has an anti-bacteria function, as do copper and silver, but copper oxide may be too powerful since it can kill landscape plants and is used in preservative treatments
  • Stainless Steel cutting boards 600 x 600 mm to cover a part of the kitchen worktop are also promoted
  • Titanium is being promoted for cutting boards (probably expensive to be whole worktops?) being scratch resistant, non-porous, easy to clean, but soft enough not to blunt stainless steel knifes
  • Avoid plastic cutting boards (ingesting plastic splinters is seriously unhealthy)
  • Avoid low density wooden chopping blocks that may suffer drying shrinkage cracks to harbour food bacteria.
  • But a professional chef will know how to clean high density wooden block well enough

Swindon Self Build & Reclamation Centre

  • Seriously consider visiting their premises
  • 200 permanent exhibition stands with all building materials technologies by manufacturers or suppliers
  • Go when a show is on to meet manufacturers on the stands.
  • There is also EcoMerchant a green building merchant out the back of the centre
  • They can advise about many products in the centre and have prices/m2 of all their products online
  • There are a few other green builder’s merchants across the UK

Brick slips are noted on the drawings

  • I would not recommend brick slips on masonry construction either internally or externally
  • Instead use whole bricks
  • Brick effect can also be achieved with render by artisans
  • Client indicated they were not going that route anymore.
  • Alternative internal finishes: clay plaster and clay finish, which offer a DIY opportunity, natural textures and natural colours, moisture management and moisture permeability.

Case Study

  • I suggested they keep records and take audio/photographs/videos
  • We are always interested in lessons learned good and bad.
  • And turn it all into a case study on https://GreenBuildingEncyclopaedia.uk
  • I will post an anonymised version of this paper there now and add to it later

© GBE NGS ASWS Brian Murphy aka BrianSpecMan
17th June 2025 – 19th June 2025

Proposed or current actions:

  • Paper being removed
  • Propose to remove the chimney breasts.
  • Needs new roof and guttering.
  • Proposing to remove gypsum plaster
  • Proposed to batten out and insulate inner face of external wall
  • Considering sheep’s wool as Internal Wall Insulation IWI

PS Further explorations:

Party Wall Survey, PW Structure Notice, Party wall agreement, Party wall awards

  • The ambition to remove the chimney breasts can lead to damage to the other party’s half of the party wall.
  • Depending upon the dimensions the chimney flues may be interlaced or in two parallel lines.
  • Interlaced flues will make the removal of your side of the chimney breast more challenging.
  • The party wall survey is essential and can include a measured survey, photographs at roof level and internally to record the state of repair and the geometry.
  • Consider what happens and will happen at foundation, ground floor, upper floor, ceiling, attic and roof levels allow to carryout remedial work in all cases.
  • It will form part of the Party Wall Agreement and be used to show the existing, compare with the aftermath and determine any compensation for changes that occur due to the works.
  • https://www.gov.uk/government/publications/preventing-and-resolving-disputes-in-relation-to-party-walls
  • Party walls can be a large heat loss if the adjacent building is unoccupied, but if we assume it is occupied and heated then the heat transfer between houses through the party wall is negligible, however at the external wall junction it may be useful to add insulation to the party wall to reduce the thermal bridge at the party wall/external wall abutment.
  • If the party wall is not insulated it can be exploited for thermal, acoustic and moisture mass, after removing any gypsum plaster consider applying clay or lime plaster, for airtightness with improved acoustics, for thermal mass to hold excess heat and moisture mass to regulate humidity.
  • With the right insulation materials and finishes all these issues can be addressed with one system.
  • Earth and cork granule internal plaster is multifunctional.
  • Diasen’s Diathonite Evolution (PASS) https://greenbuildingencyclopaedia.uk/?p=433

PS Roof coverings and gutter

  • Victorian terraces most often have roofing slates which are thin and relatively lightweight
  • Reroofing can be with the same slates, although some will probably be damaged taking them off.
  • Some additional slates can be obtained from Architectural Salvage Yards
  • https://www.salvoweb.com/salvo-directory/category/all/location/uk/region/all?q=roofing%20slates
  • Replacing roofing slates with heavier concrete or clay tiles will overload the roof timbers unless you replace the timbers too.
  • Timber suffers from creep and will move away from the load over a long time and some details may suffer weather leakage.
  • Avoid switching to metal roofing tiles which will be lightweight but offer no protection from solar gains via the roof tiles.

PS Suspended Floors:

  • Inspection will determine the direction of boards and joists any trimming around the chimney breasts and staircase.
  • Check for any damp or mould in timbers
  • Upper floor will show up any air leakiness and the need for insulating the floor (thermal or acoustic and at perimeter)
  • Ground floor will show up any air leakiness and the need to insulate the floor.
  • Where you are insulating walls with IWI make sure you address the thermal bridge in the floor zones.
  • Enviroform Solutions Ltd. https://greenbuildingencyclopaedia.uk/?p=4728
  • Thermo-Joist: Foil wrapped aerogel
  • https://prezi.com/dlmqm33k8vgn/copy-of-introducing-enviroform-solutions/

PS Attic:

Proposed interventions:

Domestic Hot water

PS Window & Door Jambs

Other links

Insulation:

© GBE GBC GRC GIC GGC GBL NGS ASWS Brian Murphy aka BrianSpecMan ******
19th June 2025

Images:

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© GBE GBC GRC GIC GGC GBL NGS ASWS Brian Murphy aka BrianSpecMan ******
19th June 2025

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© GBE GBC GRC GIC GGC GBL NGS ASWS Brian Murphy aka BrianSpecMan ******
19th June 2025

Mid Terrace 1950 (Brainstorm) G#42526 End.

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