Repairs: walls

If the movement is ongoing, the structure needs to be stabilised before proceeding. A temporary support – screwjacks or raking shores/buttresses, if appropriate – should be adequate for most circumstances.

If the problem has arisen because the soldier course has dropped or the keystone pointing has weathered away, it is usually easy to repair. Adequate and safe access may be the greatest difficulty for working at height.

Check that the arch finishes at the wall reveals, as it was designed to do. Often an opening has been previously widened to ease in a wider window or door salvaged from elsewhere. If so, the arch may not be repairable without rebuilding the reveals to support the side thrust from the arch.

Check the condition of a timber backing lintel if there is one. If decayed by contact with damp solid wall surfaces, then replacement with a modern steel box lintel or reinforced concrete (RC) lintel behind the facework arch may be more appropriate.

Solution 1

Temporary support will be needed – a cantilevered screwjack is probably most convenient in this instance, located within the building and set into the wall from the inside face to support and take up the load temporarily while work is being completed. If working on timber floors the screwjacks will need adequate support and a load path down to something solid, or use timber load spreading plates.

An engineering calculation is appropriate if floor joists are in very poor condition (or you may need a temporary working scaffold both inside and outside the structure).

It should be fairly simple to deconstruct some or all of the arch once the floor and wall load has been relieved. The arch can then be rebuilt using a timber former. If the bricks have been 'rubbed' and set to a tapering gauge, then if they cannot be salvaged, rubbing in new brick is comparatively simple for a skilled bricklayer, but it will add to the time and cost.

Once the mortar has set, supports can be struck.

Solution 2

Stainless steel helical bars offer a couple of repair options:

• The bars can be embedded in the mortar courses at vertical intervals and secured in an epoxy-modified mortar within the joint before remaking the face pointing to match the original. This helps to create a beam across the top of the arch and relieve the load permanently so that the brick detail does not have to work quite so hard in the future.
• The brick or stone arch can be drilled at an angle and helical bars skewed into the masonry and glued in with an epoxy or polyester resin to physically lock the bricks together. This is especially useful if the arch has not yet failed, but it will need repointing, and there is a risk of further mortar dropping out and the arch sagging during the work.

Helical bars could be used to mechanically fix a dropped brick arch

Cost sequence - Dropped/depressed brick window/door

1. Provide temporary support to depressed arch using, for example, screw jack with profiled timber formed beneath the arch-soffit.
2. Carefully chase out the mortar courses above the brick arch using an electrician's bolster/chasing bolster or similar. Allow for chasing 2 courses in the horizontal bed joints, separated by 2 courses depth above the arch.
3. Chase the depth to about one third/half bed joint.
4. Carefully brush out and wet the chases. Using epoxy resin-modified mortar, prepare the back of the joint. Install helical stainless steel reinforcing bar to each joint and regrout and finish point each chase.
5. Extend the chases nominally 300mm beyond each side of the brick arch. (Large spans might need more.)
6. Jack the brick arch into position once the helical fixings have formed a relieving arch above the brick arch. Carefully break out and chase away any loose mortar. Wet out joints and regrout. Fair finish/repoint the wall to match the existing/original style of the pointing.
7. When all grouting has cured and masonry is secured by adhesion, then allow for drilling in of, say, 8 helical bars to be skew-fixed through the arch to provide additional mechanical fixing. Allow for coloured-in pointing to be the face of the brick to re-secure and provide re-cosmetic finish and prevent entry of water to masonry.

Dropped/depressed brick window/door arch - COST £480

Small works pricing

Since the original price estimating in 2008 the economic turmoil of the last few years has caused some disparities in pricing - if you are reviewing these figures in the London area they may look laughable - if you are located in Hull they might still look a bit expensive. Please treat them with caution and of course always consider obtaining more than one quote against which to test prices. Reference to the BCIS or a small works pricing book such as Spons or Laxton's will help assess costs and the hourly labour rates upon which they are based.