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Larch and Lime passivhauses

Larch house entrance

Larch house entrance

Although not self build, the two passivhauses at Ebbw Vale may be very relevant to many self builders. Built in 2010 as show houses mainly for the attention of housing associations, they are attractive and innovative while being relatively modest. The 3 bed Larch House is clad with a locally sourced larch rain screen and Lime House has a natural lime render.

Considerable effort has been put into using local materials where possible and also enabling local businesses to learn the new techniques required for services, timber frame manufacturing and window/door production etc.

Larch House not only achieves the Passivhaus standard but is also zero carbon due to the large areas of solar collectors on the roofs. This achieves CSH Level 6,  a UK first. Lime House achieves CSH level 5

Larch house

Larch House

Larch House south elevation

The south elevation of Larch House has more than 50% of its surface glazed with certified triple glazed windows to catch winter sun. Louvre blinds are fitted to prevent overheating in summer. The main construction is 225mm glass wool insulated closed timber frame with extra wood fibre insulation board on the outside. The external walls total about 450mm thick with a U-value of 0.1W/m²K. The air tightness test achieved a remarkable 0.2 ac/h @n50

The other elevations have low levels of glazing.

north and west elevations

Larch House north and west elevations

patio doors

Partly lowered solar blinds above the patio doors. The window liners help reflect light into the rooms


Lime house

A slightly different approach was taken here. The UK climate (and particularly the somewhat higher altitude of this location) tends to be more overcast than in mainland Europe where the Passivhaus standard is most often applied and south facing passive solar gain is relatively less important so glazing was not used to the same extent as the Larch House: rather the heating relies more on internal heat gains and higher insulation values

Lime House

Lime House south elevation

The space given over to the MVHR is quite considerable. Both houses used one of the most efficient heat exchangers available. The Paul unit is rated at over 92% efficient. This is the grey box in the picture with the heavily insulated black ducting. The silver unit is the heater for the incoming air after it has been through the heat exchanger. Note also on the left the orange pipework for the fire sprinkler system which is becoming mandatory for all new housing in Wales.


United Wesh

bere:architects – Lime House – general information

bere:architects – Larch House – general information

1 comment to Larch and Lime passivhauses

  • phil walsh

    I am considering converting a stable block into a wooden eco house – 3/4 bedrooms – 2 bathromms – 2 loos – attractive open plan design. The possible site is on the side of a down.
    I have ni idea of what it might cost.
    I know that every building is different.
    But it would be helpful if when looking at your gallery there was some indication as to what it might cost to design &construct such a property.
    Any ideas

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