Thursday 6 October 2016

Up on the Roof

The saga of the north facing ventilation continues!

In an attempt to minimise direct rain penetration, in consultation with the boss of the window frame company, the builder devised a canopy extension system for the three vents. This was fabricated off site and then installed and welded up on site. In addition to providing a degree of shelter to the vent opening, it was also to provide a way to retain the soil covering over the waterproofing layer on the ventilation shafts.

Some of the welds gave out within a week without any rain adding weight to the structure!

The window frame company's contribution, after much deliberation, was to come along and drill and plug a number of "drainage" holes at the bottom of the frame supporting the outer "doors" so that if water does penetrate it will drain away rather than accumulate. Given that the earth level adjacent to these frames is only a little below the base of the frames the potential problem in heavy rain is obvious!

So now, an initially straightforward solution of using windows as a ventilation system requires an additional "door" opening from outside, with drainage holes drilled in the frame, and a canopy system to limit direct rain penetration for each of the three ventilation shafts.

This is getting unreal. 

To add to this whole saga is the fact that the mechanisms to open the vents from inside the house are not fit for purpose. It has not proved possible using the long thin winding handle to exert sufficient pressure to consistently fully close the vents. On top of that the mechanisms themselves have started to break!!

The result has been that the vents have not been used throughout the long hot summer as it was too great a risk to not be able to fully close the windows, especially given last year's torrential summer rain and the resulting flooding of the house. (See earlier post).

A rethink is required.

When the roof was covered with its earth sheltering layer, the section of the roof at the front of the house was overfilled with earth. The result was that when there was heavy rain, washing down the hillside and across the roof, water and mud were washed over the parapet and ran down the front facing of the house, leaving muddy trails and depositing said mud and water onto the terrace. Whilst the discolouration of the front facing concrete helped to temper the stark outline of the house by blending it into the hillside, it was not a suitable long term arrangement that reflected the clean, sharp line design statement of the house!!

The solution, here, was to dig out 50cm of the soil against the front parapet to a depth of 20cm, set a narrow aluminium sheet "wall", with drainage holes drilled in it, some 15cm back from the parapet, fill the space between this "wall" and the earth covering with gravel to retain the soil but allow any water to flow through. A drilled drainage pipe was then bedded on gravel along the whole length of the house to collect and run off any accumulated water at either end of the house.

We are now awaiting some heavy rain to check that all works as planned.

And finally...

Whilst having a quiet lunch one day there was a loud crash from the room transmitted down the cook stove chimney. Fearing the worst, with the PV and water heater panels located where the sound seemed to originate from, I rushed up to the roof. What I found was that the thick polythene cover that had been battened into place as a temporary measure, to prevent soil and rocks falling into the light well when the earth sheltering was being put in place, had been ripped off by the high wind and a batten had collided with, and dented, the chimney stack. Hence the loud noise.

With this temporary cover removed, more light was penetrating into the study area and the removal of the greenhouse effect means that there is a cooler flow of air into this area. Which, given the problems with the north facing ventilation highlighted above, has proved most beneficial.

The latest attempt by builders to protect the north facing ventilation system from the ingress of rain and mud.

Problems remain with the flow of the soil used to cover the top of the ventilation  shafts. This is a week after job was completed and before any rain wash down.

After a week this welded seam on the aluminium overhang had given way. Again without rain to add any pressure.

The temporary "roof" over the light well was ripped off in the fierce summer winds.

The new look light well.

The new front of roof drainage system installed to prevent the flow of mud and water off the section of the roof that was overfilled when the earth sheltering was installed.

View, looking east, across the roof.