Implications of raising roof height on already converted loft space

popularfurball

We are looking at a property which potentially has everything we want within it - except it is two bedroom, rather than four.

However, the two bedrooms are 20"2 x 10"10 and 20"2 x 12"8 so feasibly would divide into either four doubles, or two large doubles and two singles - more than meeting our needs. The two bedrooms are upstairs on the first floor along with the bathroom. There is no loft space above this.

The building is a barn conversion, and as a result the ceiling height restricts the head height currently - thus its not possible to have more than two bedrooms currently. The edge of the rooms are approx 4ft in height, so we would have to raise the roof by 2-3 feet.

Planning team stated that going up would be ok to bring in line with adjacent properties - but not outwards as it is green belt land.

What are the costs and the considerations we need to make for this type of work?

Doozergirl

How much floorspace are you feasibly going to gain by raising the roof?

We're talking big sums. We have replaced roof trusses in a barn converion to create rooms in the loft space. It was financially viable because we created floorspace where there was none. The cost was comfortably six figures, even allowing for the renovation downstairs. Floorspace of around 1000 square feet.

In all honesty, it may not be far off rebuild cost if you have to underpin the foundations to hold new brickwork.

leveller2911

When you say "raise the roof height" do you mean increasing the pitch (angle) of the roof to allow for increased headroom? or do you mean increasing the height of the outside stud walls and pitching a new roof with the same/similar pitch as the existing?.

If your plan is to just increase the pitch of the roof then cost wise it should be huge. In the past I have done this by pitching the new roof over the top of the existing roof so the house is weather tight and then taking down the old roof afterwards. As long as you have space for a staircase up to the new loft I'm sure it can be done fairly cheaply compared to extensions etc.

If you can do this you shouldn't need to increase the foundations because there is little increase in loadings but obviously you would need building regs etc.

popularfurball

The area/floor is already converted - and recently - so I am hoping that the foundations are sufficient. It also has a decent slate roof on it (which would have to remain due to planning constraints I suspect).

The materials (I think!) would be the extra bricks required around the edge and the two dividing walls to split the rooms up and two doors...

I am not sure on the floor space - how would I calculate this?

The rooms look like this


Planning have said that the "roof could be raised in keeping with the adjacent house's roof line". My interpretation of this is we would need to raise the ridge height as well as the exterior walls - but perhaps changing the tilt would be sufficient?

leveller2911

You won't gain much by just raising the ridge height so you would either need to raise the outside walls and ridge height to gain much benefit. Will the planners allow you to fit a couple of Dormar windows with pitched roofs on ,rather than flat roofs on each side of the room?.

This will give you more headroom and be cheaper compared to the other options you have suggested.

popularfurball

No, dormers are "not in keeping" with the area...

Sorry I didn't write my above response clearly - I think our options are:

1) raise ridge height and exterior wall height
2) raise exterior wall height and change roof angle

The actual ridge height is pretty high I think - would changing the roof tilt be enough to gain sufficient space?

What kind of ball part figures would we be looking at?

Doozergirl

Dormers are not in keeping with barn conversions. Barn conversions usually have their permitted development rights removed so that everything needs permission.

I think you're on a hiding to nothing with this. Either you need to find ways to change the internals of the house to accommodate more bedrooms - it sounds like the dimensions are there but more imagination is needed, or, I suggest, you walk away.

It really isn't just bricks and stud walls! It's skips, waste removal, bricks, insulation, wall ties, new trusses to meet current building regulations, solid insulation between the rafters, plasterboarding the entire pitch of the roof, then the new walls and doors, breathable membrane, new tiles for the increased pitch and damaged originals, a rewire - partial or full, replumbing of upstairs. Oh, and maybe underpinning the entire house! The undertaking is insane in comparison to any gain.

Increase the pitch of the roof and you will gain maybe a metre in total down the two sides. Raise the walls and you might gain two metres. If you draw yourself a cross section of the roof to scale, mark the height of the neighbours ridge line and draw yourself a roof line and consider 1.5metres to be useable headheight at the edges, you can work out exactly what you gain. Lots of maths for you to practice!

To calculate floor area, you either look at the floorplan which hopefully has it or you multiply the length of the house by the width. You can usually guesstimate with room dimensions in the estate agents details.

If the barn already had a roof when it was converteed, there would have been no need to underpin foundations unless it was subsiding.

Presuming this barn is much longer than it is wide, two staircases instead of one might get you the four bedrooms. The bedrooms will be separated but it isn't unusual in a barn.

popularfurball

This is a (very badly drawn) plan of the first floor as it is currently.
The floor was added when converted - it wasn't in the property prior to conversion

http://i1098.photobucket.com/albums/g375/popularfurballvideo/B416C607-34F4-42DB-8D65-7054FB53FB8E_zpscstrzhru.jpg

Here is my idea of what would happen with the building - open that landing out a little to accommodate the extra doors?

http://i1098.photobucket.com/albums/g375/popularfurballvideo/19799DD0-2124-4510-9B3E-822D5B2E330E_zps1sc26ara.jpg

As for the value, the neighbouring 3-4 bedrooms are up for upwards of £175k extra so I'm not worried about the added value but our restriction will be on us paying for the work in the first place!!!

The other "complication" is it is the only property locally with land (a couple of acres) we can afford currently (and our hand is being forced so we have to sell ours now due to ongoing developments nearby). I am aware tht most people would never be able to afford land an we are extremely lucky, and also that we are probably being cheeky trying to get what we want on such a tight budget really.