Roof Report For: XX Como Road, London, SE23 2JL. ON BEHALF OF: Mr & Mrs A. Example

Transcription

1 Roof Report For: XX Como Road, London, SE23 2JL ON BEHALF OF: Mr & Mrs A. Example FLAT F, 110 BLUEHOUSE LANE, OXTED (tel) ( ) (web) 1

2 Roof Plan Below is a labeled plan of the roof relating to this report. This can be used to identify and more clearly understand the report on the roof condition that follows. This plan is not drawn to scale and should only be used to better understand the areas in question. Rear addition Main slope (rear) Chimney Stack Pediment Parapet Walls Main slope (front) Front of property (street) Notes of observation The roof on this semi-detached property is of timber construction, overlaid with 1F underlay felt, wooden battens and Redland/LaFarge 49 tiles. Visual inspection of the timber rafters, purlins, wall plates, ridge beam and support struts indicate no rot or significant weakness. The Purlins sit on corbelled brickwork and seem to be in a secure state. (to better understand the roof structure referred to previously visit The property has two, two-pot chimney stacks (one on each of the main front slope and main rear slope) on the left hand side as viewed from the front and formed of bricks and mortar. Cement fillets with slips of cut plain tile form the bond between the chimney stacks and the tiles on the roof. All 4 chimney pots are capped. Ridge tiles join the front and rear main slopes at the top of the apex). There is a pediment to the front of the property, covering the bay window and connected to the main roof via zinc valley linings (which have been repaired previously using black sealant). The property has a rear addition of the same construction as the main roof. Party parapets run along the right of the property at the join of the neighbouring house. These parapets are of brick, lead and render construction. The property has plastic upvc guttering to the front/rear and rear addition slopes. The fascia boards are formed of wood. 2

3 DEFECT REPORT Main Slope Front The top render to the front party parapet wall is defective and is in need need of replacement. This exposed brickwork will lead to spalling and cracking of the bricks in time due to frost action. Frost action is a process where by water in saturated bricks freezes, expands and spalls the face of the brick off. This process, repeated, will eventually lead to the brick disintegrating. The bricks are not currently in a state of required replacement. See picture 1. This requires the hacking away of all of the old rendering, applying bonding agent and re- rendering the entire wall. The lead looks ok and should be re- useable, providing it isn t damaged when the wall is hacked off. The over- sailing course to the main slope (front) chimney requires new mortar. The 2 pot chimney on the front main slope requires some minor pointing works to repair areas where the pointing (mortar between bricks) has loosened or failed. The main area in question is the front face of this chimney. See picture 2 for evidence of this problem. This chimney has cement fillets joining the chimney to the roof with cut tile bedded in the cement. They currently appear to be water tight, but should be watched closely for cracks forming at the join and failure in the future. Lead flashings stepped into the brickwork are the ideal solution. 3

4 Main Slope (rear) As can be seen from picture 3, the over- sailing course to the chimney in the main slope (rear) requires new mortar. This chimney has cement fillet flashings with cut tile bedded in the cement. They currently appear to be water tight, but should be watched closely for failure in the future. These flashings would be more resistant to the elements if formed with lead, and stepped into the wall. The front chimney flashing should also be formed of lead. This issue is not currently problematic, but will unlikely last longer than a few more years before it fails. The same issue is mirrored in the front chimney. The ridges that join the main slope rear, with the main slope front, have been sealed with mastic in the joints. This indicates a previous problem, and they should be removed, re- bedded and re- pointed to ensure longevity. Mastic is a temporary solution and will not last longer than a year or two before becoming problematic. The general condition of the tiles to the main slope (rear) is fine. The main slope guttering (front and rear) seems to be ok and working well. Pic 4 4

5 Pediment The valleys that join the pediment to the front main slope have both been repaired in the past using a liquid applied product (probably a bituminous sealant) which would indicate previous problems to these areas. (see pics 5 & 6) The best solution in this case is to remove both valley linings (left and right) and replace them with new zinc valley linings. The tiles will need to be bedded back onto the new zinc lining using cement. The ridges to the pediment require some Some are loose and will need re- bedding. There are 3 loose ridges that need re- bedding indicated in pic 7. 5

6 Rear Addition The rendering to the back addition is loose and defective. This needs hacking off and re-rendering down over the bricks to the point of the over-sailing course. An alternative would be to remove the old render and point the side turned bricks that form the parapet wall top. There is also a plant growing out of the wall that needs removing, and the gap left must be filled. The cement fillet that joins the wall to the roof cannot be guaranteed, and would ideally be replaced with a lead flashing. Such fillets are known to crack, and for that reason, this area could become problematic in the near future The cement fillet that joins the rear addition to the house wall, looks in good condition, but once again, this area of the roof should be watched closely. This particular cement fillet, I anticipate to last for longer than 3 years. Visual obsevation indicates that the guttering and downpipes are ok and are working well. 6

7 Conclusions & Recommendations Problem Description Recommended Solution Severity All party parapet walls have defective rendering to top and patches of sides. Loose/missing pointing to front slope chimney stack. Cement Fillets to front and rear slope chimney stacks have some signs of cracking at the joins. Cement work on rear chimney over- sailing course has broken, cracked and requires replacement. The mortar gaps in the ridges that join the front and rear main slopes at the apex, have been filled with sealant mastic. Defective, previously repaired valley linings to left and right of pediment are old, cracking and require renewal. Loose ridges to pediment. Hack off all render and existing cement fillets to 3 parapet walls, fit new lead, apply bonding agent & re- render using stop bead for neat finish. Rake out all loose pointing to front chimney stack. Re- point as necessary. Remove fillets, replace tiles as necessary and fit stepped lead flashings and front apron to chimneys. Chip away what remains of cement. Form new cement to the over- sailing course top. Remove sealant from mortar joints and re- point using mortar. Strip away tiles, remove old linings, fit new zinc linings, re- lay and bed tiles using cement. Remove loose ridges, clear old mortar, re- fit ridges using new mortar. Point mortar joints. attention soon. attention soon. attention soon. This report was produced by Mr N. Morris of Roof- Smart Roofing Reports on 30/11/2010. As per the pre- report agreement Roof- Smart does not accept any liability in unforeseen works that are not described in this report. 7