Extending a wall

[Andrew May]

I need to extend an internal wall but only by about four inches. It sticks out into a kitchen and needs to be a bit longer to reduce the doorway gap. It is built from some form of concrete block, more a cinder block than thermalite and the end of each alternate row is a single upended brick. The finished wall will be plastered. As far as I can see there are several alternatives.

1 ? Cement an additional column of upended bricks to the end.

2 ? Chip out the upright bricks and cement in bits of thermalite block so it continues to be interlocking.

3 ? Screw a piece of timber to the end with spacer pieces to ensure it is in the right position. Infill with brick/cement. Then put gauze over the new section before plastering.

4 ? As 3 but hack off all the plaster and plasterboard in one go.

What does the team think would provide the best solution.

Andrew

[dom]

Yes, but no need for the brick/cement infill. Use framing timber, and lots of fixings. 50*100mm studs would be fine.

I would do this in conjunction with fitting the door frame. Masonry screws (e.g. multimonti) to fix the first stud to wall end (probably uneven/off-vertical).

Do the same for the other side of the door frame.

Then fix (big screws, e.g. 6*100mm spax) the head timber that goes directly above the door frame solidly between the two vertical timbers attached to masonry.

Then screw a second stud to the first with such spacers as necessary to bring it vertical and to the right position for the door frame.

Then any infill studs needed above the door frame.

Then plasterboard over the timber.

[Man at B&Q]

None of the above.

For 4" just do it all in timber.

MBQ

[Roger Mills]

There's little doubt in my mind that (2) is the best solution. (1) is unlikely to work because you won't get good bonding, and the new bit will crack away. I suppose that (3) *might* work. (4) sounds like a hell of a lot of work, and it's not that easy to remove plaster in a way which leaves a flat surface.

The *easiest* solution would be just to add a solid bit of timber of the right size and clad it with plasterboard, and skim it to blend in with the original plaster. The only problem with that is that - over time - you'll get hairine cracks between the old and new bits.

[Andrew May]

There is no door frame. It is open plan with an opening between kitchen and dining room but I want the gap slightly narrower so it can be covered by a vertical blind to hid the mess.

Andrew

[Tim Watts]

Roger Mills wibbled on Friday 12 February 2010 11:37

There is an intermediate solution:

Drill a vertical column of holes up the end of the blockwork, so that each hole will align with a brick course mortar joint. Aim for one hole every 2-3 bricks.

Resin in a length of stud (M10-M12) inserting about 4" into the block and leaving about 4" protruding. Build brickwork incorporating stud well into the mortar joint - I would (and have) break all the rules and use a 3:1 mix and damp the bricks down first for a max strength joint.

I interlocked properly when I did a similar job, but that was to an existing brick wall, so it was a simple matter to take out the half bricks. I used the resin+stud trick though when reducing a window opening leaf and had to use upended bricks rotated 90 degrees - ie reduce by the brick depth rather than the width. I feel reasonably confident it will work quite well in this application. With interlocking the bricks, you will be able to belt it with a clubhammer and it wont move (given a couple of weeks set). With the resin+studs, it won't be *that* strong but it will probably be stronger than a lot of other methods...

[Toby]

If you leave a hollow column, then it can be used as a riser for cables/pipes if this is of use.

[NT]

Another optoin is just thick plaster or cement over EML. With a good thick depth its very tough.

NT

[Steve Walker]

Buy a bigger blind....?

[Andrew May]

Actually it's the opposite problem. The blinds are these big sheets that hang of a rail (I'm sure they have a technical name) They are 600mm wide but the wall is only 500mm and it would (would have been) nice to have them completely out of the way when slid back.

I say would have been because the current idea is to still extend the wall but far enough to put a 600mm pull-out larder next to it to create a bit more storage space.

May still be looking for some way to separate off the kitchen though.

Andrew