What about the diagonal beam under the roof? As explained in yesterday's blog post despite all care, the whole structure was skewed and while both diagonals at the bottom were as precisely the same as can be (to 1 mm), at the top the diagonals differed by some 2 cm! This was fixed by putting the beam in place after cutting it to exactly the correct length of the diagonal. Once installed, both diagonals matched also at the top.
Now that everything is in place and the roof is on, the tension's gone elsewhere and the diagonal beam is lying loose without any pressure on it, secured by a few nails.
By the way, the play house is a kit marketed as "Lillevilla 209" or "Lillevilla Playhouse 4", a product from Finland, which is available elsewhere in Europe, too.