Blocking Up Internal Doorways

[FergusMacdonald]

I'm blocking up 3 internal doorways. They are brick walls and suspended timber floors. I've taken the casings off and the door jamb is the same width as the wall and goes through the floorboards by the thickness of the floorboards. The plan the structural engineer put in for the building warrant states "Infill door opening with new timber panel. End studs fixed to existing wall with M12 rod FIS A Fisher FIV resin anchors for masonry @ 600mm centres or equal approved".

Would appreciate advice on the following:
1. Should I take out the door jambs completely and replace with new CLS or try and keep the jambs and use them? I could leave them as they are, put CLS on the inside and then plasterboard but would have the width of the jamb to plaster over. Alternatively I would probably need to cut away a bit from each side to have the plasterboard overlap them.

2. Should I take out the floor boards where the new wall will be?

Thanks!

 

[Ivor Windybottom]

Are you interested in sound-proofing between the rooms you're dividing? If so then brick or block would be vastly preferable. There's probably a wall below the floorboards you can build up from, remove the frame and put screw ties into the adjoining masonry.

If you go with the board then there's also a good chance of hairline cracks appearing where the plasterboard meets the solid wall over the years.

Someone on here recently was complaining about their fridge backing onto a boarded up doorway being very loud in the adjoining room. As it's almost entirely made of fresh air.

 

[Ivor Windybottom]

In answer to your question, the door lining will have to go to make space for the plasterboard to adjoin the brickwork, you can't skim over wood.

In which case, you may find out that there isn't a lintel - definitely check first. You may need to prop up then brick up, there'd be no sense in inserting a lintel just to board it up.

 

[FergusMacdonald]

The wall will separate the new kitchen to the hall so sound proofing is not an absolute but would be nice. It will have kitchen units over half of it on the kitchen side. I was thinking to infill the stud partition with rockwool to provide some sound resistance.

Good point about the lintel, I nearly added that as question 3. It is a load bearing wall. On the doorway on the opposite side of the hall there's a vertical row of bricks above the door header, but that wall is not load bearing.

 

[^woody^]

Blocking up an opening is not structural work and that spec seems way over the top.

If the linings are secure you can just build your frame within the opening. You could gloss the lining edges, or PVA and stick fibre scrim tape across them and plaster over the top.

 

[Ivor Windybottom]

The door lining is holding up the wall, so either it stays or you brick it up after propping it up.

If you skim over it then it will be guaranteed to crack through, showing the outline. But if it's covered in units and splashbacks/tiles then that possibly doesn't matter. But more of an issue on the hallway side.

Rockwool will have absolutely no effect as soundproofing. If you back a fridge, washing machine or dishwasher against it then it may boom like a loudspeaker enclosure.

If there's a footing under the floor then it would be a shame not to brick it up, I definitely would.