Good morning please could someone help I am currently doing a small loft conversion above the garage which has very low collar ties and I need to raise these to give some head room. I have spoke to a builder friend of mine and he said that is fine to raise the height but add some more in at equal lengths as extra support please could someone advise as this has caused some issues with my wife and me as she thinks the roof is going to collapse pictures attached
The collar ties are to prevent the roof spreading, the ceiling joists also do this but at the base of the roof. If the rafters are not strong enough and you remove the collar ties, the roof could tend to bulge or sag in the centre of the slope. What is the roof covered with, how heavy. Normally, when the collar tie is lifted at design stage, the rafters are enlarged to take the additional bending moments.
Thank you for your reply the roof is covered with tile honestly I don’t know exactly what kind It is stone / concrete tile not slate