"appears to mean doubled in height."
It was altered significantly inside, but I'm not sure how
I've n idea where the old bedroom was - I should imagine that it followed the Irish layout of a large all-purpose room which you entered at the centre and two small bedrooms at either end - some Irish cottages have an additional tiny loft room reached by a ladder
'Modernisation changed it to a small lobby in the centre with a flight of stairs facing the front door, a living room on the left and a kitchen/scullery on the right
Upstairs two bedrooms and a bathroom
At the far end from the road there was a coal bunker