Garden Office and Garden Studio Insulation

Insulation of Garden Studios and Offices (An important topic)

By Richard Grace Project Director Garden Structures http://www.aarco.co.uk/

It’s always been on the agenda but never more so than now. When our clients are investing their hard earned cash in a work building (Garden Office or Garden Studio) at home they always want to know:

a)     “Will it be warm and comfortable?”

b)     “Will my things be dry and protected in bad weather?”

c)      “Will it cost me a small fortune to heat?”

d)     “Will it become too hot on our best days?”

The answer is “yes if the building has a watertight roof and you control the temperature” but - it will cost more for this control without insulation. All the information I sought in preparation for this article about the importance of insulation in a single storey building reveals the following: (I guess you already know)

1.     Heat rises leaving cold air at the lowest level in a structure.

2.     Air movement in a structure tries to equalize the temperature inside and       outside.

3.     Some materials provide better resistance to temperature transfer than others.

4.     Return on investment on structural components varies

This table indicates the importance of each part of a single storey structure
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Roof	The most vital investment associated with loss of 40% heat on cold days and responsible for 80% of overheating on hot sunny days
Walls	Important should be draught and condensation free + provide adequate resistance to heat transfer in and out typically 25% of heat loss
Windows	Vital without good draught sealing and double glazing allow draughts and can lead to condensation even then responsible for 15% of heat loss
Doors	Vital (the same as windows) but need to be in constant use + resist draughts and condensation another 12% of heat input gone
Floor	Some heat is lost if floor is highly conductive and in direct contact with ground e.g. concrete exposed or single skin wood fixed to exterior beams 8% is going here

The above is my analysis data drawn from multiple professional sources and reflects the relative importance to internal comfort level of each part of the structure. You can see from this table that the ideal structure would have no draughts, a flat (highly insulated) roof at about 2.2m height, walls which are thicker at the top than the bottom and less windows than most people want. As previously stated I think we already knew this.

 

Some experience

Over the years Noella and I have lived - in a cottage in Derbyshire with stone walls two feet thick, an old chapel converted, three modern style houses of different specification, have been on holiday in a caravan, tent +++ more hotels than can be remembered. We have been overheated in a tent, frozen stiff and damp in an UN-insulated attic flat and superbly comfortable in a single skin wooden cabin we had as a showroom for six years.

If we all had an unlimited budget to build a garden office today we would both choose Structural Insulated panels with Solarflex (brand) folding doors and windows. This specification is probably the best available and with minimal heating or cooling provides a superb comfortable environment at the lowest energy cost.

At the other end of the scale a thin drafty single skin wall with drafty windows and no roof insulation would be uncomfortable on 250 days out of 365 in our climate and require expenditure of at least £300 per year to control it. (This is an ordinary garden shed)

So - let us look at another table comparing the three most common Garden Office and Garden Studio construction techniques with specifications that meet the essential criteria for Garden Offices here in the UK.

	Comfortable all year round	Save some further cost on energy	Superb Specification
Roof	Flat roof with 70mm of dense insulation	Upgrade to 150mm	SIPS
Walls	65mm of single skin pine wood	Double skin with 50mm dense insulation	SIPS
Windows	Sealed double glazed windows 10mm gap	15mm gap in double glazing with seals	Triple Glazing
Doors	Same spec as windows	Same spec as windows	Triple Glazing
Floor	Two layers with some insulation	40mm dense insulation	SIPS
Cost per sq m installed project	£700	£900	£1100
3m*4m Office Total Project inc VAT	£8400	£10800	£13200

We are asked about electrical systems, security, maintenance etc.on each and every client site-visit. All of the answers are simple but the explanation of insulation importance and ROI remains the hot (in more than one way) topic of the day.

Richard Checked May 2017  richardgrace1@gmail.com