m_c

21-08-2012, 06:50 PM

Following on from a couple other workshop threads on here, I'm really wanting to sort out some insulation and heating ready for this winter.

The current workshop is aprox. 10.5m long x 3.5 wide x 2.2 high, and is a lean to onto an existing single brick unheated building, with the other walls being single thickness breezeblock, and one end having pretty much full width 19mm ply doors (one of those temp jobs that has remained more permanent!). The roof is coated corrugated metal, with a layer of foil bubblewrap insulation underneath. There is a single width doorway into the other building, which currently has no door.

I can't afford to insulate it all, however I want to figure out where I need to concentrate priorties, so using Heat Loss through Building Elements due to Transmission (http://www.engineeringtoolbox.com/heat-loss-transmission-d_748.html) as suggested by irving, here's the heat loss calcs.

Wall area

long wall = 10.5 x 2.2 = 23.1sq/m

short wall = 2.2 x 3.5 = 7.7sq/m

So ignoring the door opening, total wall area is 53.9sq/m.

Now taking a R-value of 0.2per inch (a quick bit googling puts brick and breeze blocks around the same value), gives a U value of 1.25.

So taking the equation Ht = U x A x Dt = 5 x 53.9 x 20 (seems to be a common standard for calcs) = 1347W

Roof area

Area = 10.5 x 3.3 = 36.75sq/m

Now taking the corrugated metal (R=8.5), and the insulation (R=0.125), U = 1 /(8.5 + 0.125) = 0.116

So heat loss = 36.75 x 0.116 x 20 = 85W

(this doesn't seem right, however now I think about it, having the space heater running didn't really affect the snow lying on the roof...)

Main Door

Area = 3 x 2 (aprox. sizes) = 6sq/m

R value of 19mm ply is 0.93, so the U is 1.07.

Heatloss = 6 x 1.07 x 20 = 128W

Now some of those results seem a bit wrong to me (anybody feel free to correct them!), however it really means I need to find an internal door, and sort the draughts, followed by getting the walls lined.

I was going to do the roof first, but those calcs show it really isn't the main problem.

The current workshop is aprox. 10.5m long x 3.5 wide x 2.2 high, and is a lean to onto an existing single brick unheated building, with the other walls being single thickness breezeblock, and one end having pretty much full width 19mm ply doors (one of those temp jobs that has remained more permanent!). The roof is coated corrugated metal, with a layer of foil bubblewrap insulation underneath. There is a single width doorway into the other building, which currently has no door.

I can't afford to insulate it all, however I want to figure out where I need to concentrate priorties, so using Heat Loss through Building Elements due to Transmission (http://www.engineeringtoolbox.com/heat-loss-transmission-d_748.html) as suggested by irving, here's the heat loss calcs.

Wall area

long wall = 10.5 x 2.2 = 23.1sq/m

short wall = 2.2 x 3.5 = 7.7sq/m

So ignoring the door opening, total wall area is 53.9sq/m.

Now taking a R-value of 0.2per inch (a quick bit googling puts brick and breeze blocks around the same value), gives a U value of 1.25.

So taking the equation Ht = U x A x Dt = 5 x 53.9 x 20 (seems to be a common standard for calcs) = 1347W

Roof area

Area = 10.5 x 3.3 = 36.75sq/m

Now taking the corrugated metal (R=8.5), and the insulation (R=0.125), U = 1 /(8.5 + 0.125) = 0.116

So heat loss = 36.75 x 0.116 x 20 = 85W

(this doesn't seem right, however now I think about it, having the space heater running didn't really affect the snow lying on the roof...)

Main Door

Area = 3 x 2 (aprox. sizes) = 6sq/m

R value of 19mm ply is 0.93, so the U is 1.07.

Heatloss = 6 x 1.07 x 20 = 128W

Now some of those results seem a bit wrong to me (anybody feel free to correct them!), however it really means I need to find an internal door, and sort the draughts, followed by getting the walls lined.

I was going to do the roof first, but those calcs show it really isn't the main problem.